M109A6 test bed for XM907 ERCA

[Kat Tsun]

You seem to be misunderstanding something. I'm saying that tactical nukes used by the Red Army would result in nukes dropping on Moscow 100% of the time.

Yes, this was known, and the loss of the CPSU was a sacrifice the Red Army was prepared to make. Good armies plan to fight without political leadership telling them to do things, because it ensures a military response is assured, even in the event of a decapitation strike.

That was the cause of the freakout in the Red Army.

There wasn't a "freakout" at all? RK-55 and other weapons were just delayed until the 1990's, after the USSR decided to dissolve itself.

The Red Army planned to fight under nuclear conditions, and if necessary, post-nuclear conditions. The USSR had a comprehensive civil defense, massive distributed stockpiles of materiel and munitions, and expected that at least some portions of the USSR would survive a nuclear exchange. Mostly this planning was led by the Red Army after Brezhnev because it became obvious that the CPSU would not survive the war.

The Red Army expected to fight and win a nuclear war. If that means a brigade of T-62s from Uzbekistan are the thing that conquers Bonn, so be it. The CPSU tried very hard to prevent a nuclear war from occurring and succeeded.

As I said, it's a tangent, but it's an alternative viewpoint to the distinctly American (and Western European) idea that nuclear war means an end to all human society, rather than an inflection point in power disparity between two competing systems that allows the weaker system to overcome the stronger one.

My point about the ERCA and using nuclear weapons is that if you're going to have a small batch weapon that is specialized in purpose, it makes more sense to make it a nuclear weapon, rather than a conventional munition. Nuclear weapons are only going to be procured in small quantities and never expended in training, and can be stored for literal decades without significant degradation. Conventional weapons, even high performance ones like PGMs or cassette munitions, require at least a one to one ratio for each enemy system you need to kill. Only nuclear weapons can achieve multiple kills on enemy systems per munition reliably.

Making it a strategic system for a Corps or Theater commander to use wouldn't require altering the initial basis of issue. Functionally, it would just be a return of the 8" guns, and the 100-150 odd tactical nukes, that U.S. corps commanders had in the 1980's. Maybe multiplied by a few times over, but America's enemies have a lot more tanks and troops than America has conventional shells to spare, given it can barely keep up with Ukraine's demands.

Perhaps that is what ERCA will become once the Army realizes that cannons stop being "dozens of rounds" cheap at around 70 km.

 

[Scott Kenny]

Yes, this was known. The loss of the CPSU was a sacrifice the Red Army was prepared to make.

No great loss there, I'd generally join them in being willing to make that sacrifice.

There wasn't a "freakout" at all? RK-55 and other weapons were just delayed until the 1990's, after the USSR decided to dissolve itself.

The Red Army planned to fight under nuclear conditions, and if necessary, post-nuclear conditions. The USSR had a comprehensive civil defense, massive distributed stockpiles of materiel and munitions, and expected that at least some portions of the USSR would survive a nuclear exchange. Mostly this planning was led by the Red Army after Brezhnev because it became obvious that the CPSU would not survive the war.

The Red Army expected to fight and win a nuclear war. If that means a brigade of T-62s from Uzbekistan are the thing that conquers Bonn, so be it. The CPSU tried very hard to prevent a nuclear war from occurring and succeeded.

As I said, it's a tangent, but it's an alternative viewpoint to the distinctly American (and Western European) idea that nuclear war means an end to all human society, rather than an inflection point in power disparity between two competing systems that allows the weaker system to overcome the stronger one.

My point about the ERCA and using nuclear weapons is that if you're going to have a small batch weapon that is specialized in purpose, it makes more sense to make it a nuclear weapon, rather than a conventional munition. Nuclear weapons are only going to be procured in small quantities and never expended in training, and can be stored for literal decades without significant degradation.

Making it a strategic system for a Corps or Theater commander to use wouldn't require altering the initial basis of issue. Functionally, it would just be a return of the 8" guns and the 100-150 odd tactical nukes that U.S. corps commanders had in the 1980's, multiplied by a few times over.

Perhaps that is what ERCA will become once the Army realizes that cannons stop being "dozens of rounds" cheap at around 70 km.

If all your long range system has is nuclear rounds, then it's never going to be used by the US. Unless some idiot has decided to nuke a NATO member already in the engagement, in which case the strategic nukes are already flying.

 

[Kat Tsun]

If all your long range system has is nuclear rounds, then it's never going to be used by the US.

I guess MGM-52's W70 and M110's W79 were just filled with confetti then?

Anyway, not using the nuclear rounds is generally everyone's acceptable SOP, because most nations are run by political apparatuses that wish to survive, while relatively few are run by general staffs that care about winning a war no matter the sacrifices.

Unless some idiot has decided to nuke a NATO member already in the engagement, in which case the strategic nukes are already flying.

Yes, that's the point.

The Red Army expected it would survive a strategic exchange, and be able to conduct further offensives, just limited in scale due to the damages to infrastructure and troop losses. It would do this without the CPSU, and most urban centers (although the urban peripheries would possibly survive), as the NATO armies would.

The assumed preference would be that the ability of the Strategic Rocket Forces and submarine forces to survive first strikes would allow the MOD to destroy most of America's coastal cities, primarily on the East Coast, with saturation bombardments by SS-18s and RSM-39s. Nuclear exchanges could theoretically be limited to tactical and operational weapon use (artillery shells and Pershings), with the USSR's own advantage in regional nuclear weapons being the "deterrent" there, and Pavel Podvig has written about this.

Point is, the Red Army wouldn't just stop because it got nuked, or because Moscow was gone. I don't think the U.S. Army thought any different, at least at the time, as it bought loads of tactical nukes from the Department of Energy, too. Nor do I think the U.S. Army or U.S. Navy would just give up because they couldn't talk to Washington or San Diego on a radio. The higher the stakes a war has, the more likely people are to keep fighting about it, after all.

But as I said, this was a tangent.

It's mostly just to point out that there are (very serious) people in the world who think that nuclear war is perfectly winnable, and preferable to government change, or the embarrassment of losing a minor imperial vassal. These people also happen to coincidentally be general staffs and government legislators.

Also, to point out that if the U.S. were serious about ERCA as a Corps weapon, it would have considered a nuclear shell. Because U.S. corps commanders probably won't have enough conventional ammunition to seriously degrade a major offensive, or conduct a large-scale attack, if Ukraine is any metric to gauge it by. ERCA is a gun seemingly built for Ukraine-style battles, too.\

But the actual reason ERCA exists is because the generals in charge are reading DIA reports from, uh, dubious at best sources claiming absurd performance or industrial capability figures from China and Russia respectively. Like SLRC it's a symptom of America's inability to properly conceptualize future wars, and this just means it will have a lot of rust to shake off when the next Kasserine Pass or Pusan Perimeter happens.

 

[Scott Kenny]

I guess MGM-52's W70 and M110's W79 were just filled with confetti then?

MGM-52 and M110s had things other than nuclear shells to throw.

I was understanding you to say that the ONLY shell for ERCA should be nuclear.

It's mostly just to point out that there are (very serious) people in the world who think that nuclear war is perfectly winnable, and preferable to government change, or the embarrassment of losing a minor imperial vassal. These people also happen to coincidentally be general staffs and government legislators.

They're also fucking insane.

Also, to point out that if the U.S. were serious about ERCA as a Corps weapon, it would have considered a nuclear shell. Because U.S. corps commanders probably won't have enough conventional ammunition to seriously degrade a major offensive, or conduct a large-scale attack, if Ukraine is any metric to gauge it by. ERCA is a gun seemingly built for Ukraine-style battles, too.\

But the actual reason ERCA exists is because the generals in charge are reading DIA reports from, uh, dubious at best sources claiming absurd performance or industrial capability figures from China and Russia respectively.

Like SLRC it's a symptom of America's inability to properly conceptualize future wars. This just means it will have a lot of rust to shake off when the next Kasserine Pass or Pusan Perimeter happens.

That would have required a president who was willing to countermand the EO stopping the design of new nuclear warheads, and possibly even having the US leave the Comprehensive Nuclear Test Ban Treaty, if the warhead design ends up very different from previous nuclear artillery shells.

 

[Kat Tsun]

MGM-52 and M110s had things other than nuclear shells to throw.

I was understanding you to say that the ONLY shell for ERCA should be nuclear.

Given its conceptualized role, the closest historical analogy is Lance.

Lance had conventional warheads, but no one expected them to be used much, because the point was to give the corps commander a few hundred nukes to sling to end a battle in his favor. Because it's a long range Corps fire support weapon, not a divisional gun, with an anticipated range of 70-155 km, it will be attacking deep area targets like battalion, brigade, and division assembly areas, railroad junctions, C3I command posts, assault aviation regiments, and long range air defense systems. All targets Lance wanted to hit.

If they can fit something like Damocles inside a 155mm shell it might be useful for counter-battery, but only in a very limited fashion. PGMs are expensive. Even then, rocket artillery is usually preferred for counter-battery, because it can fire a massive amount of ordnance rapidly and displace, and expect that ordnance to hit a target quickly and near simultaneously. This is harder with a cannon but a wide area search system like Damocles could work. Might need to nix the EFP for a Thales Fury or something though.

They're also fucking insane.

Only if you think nuclear war will somehow end all life or whatever. The more likely outcome is that anyone hit with a substantial amount of nuclear weapons just turns into Russia in the 1990's, or Japan in the 1950's, or something similar, and becomes a regional power pretty much permanently. It would still be able to sling military muscle in the near abroad but little else.

That would have required a president who was willing to countermand the EO stopping the design of new nuclear warheads, and possibly even having the US leave the Comprehensive Nuclear Test Ban Treaty, if the warhead design ends up very different from previous nuclear artillery shells.

No, it would have required the U.S. to not purchase AFAPs or W70s and rely solely on the conventional cassette warheads of these weapons. Considering the U.S. did exactly that with MGM-140 and the 155mm guns (W82) in the Reagan administration, this is not impossible in the slightest, so something changed with American calculus in the 1980's to make it decide tactical nuclear weapons were infeasible.

This is with the foreknowledge at the time that the USSR would continue existing, at least, for another 30 years as well.

Democratic armies are uniquely vulnerable to attack through intelligence pathways, though, as ERCA proves: its entire genesis relies on DIA being duped by the Russians and Chinese into thinking they have better guns than they actually do. To a lesser extent, the tactical nuclear weapons dismissal by Reagan in the 1980's is another attack by a foreign power through an intelligence pathway.

ERCA has no practical military purposes, except that it was designed to outshoot the supposed manufacturer-provided performances of the PLZ-52 and the Koalitsiya-SV, two guns that either do not approach what they claim in reality (due to lack of specialized shells) or do not exist in sizeable quantity. It does this by a very inefficient mechanism: a massive powder charge and high muzzle velocity, when a subcaliber round fired from an L/52 (as, allegedly, "demonstrated" by the PLAGF) can do the same job.

The idea that PLZ-52 is just another defense contractor bigging up their brochure with nonsense that has no practical value, and Koalitsiya-SV will remain an unmanufactured prototype well into the next decade, simply did not cross these people's minds.

Yet that is the threat ERCA is designed to "meet". The idea that they could simply purchase an off-the-shell M109I7 or Pzh 2000 and slap it into an M109 also did not cross these people's minds, because they "need" to "overmatch" these mostly imaginary threats.

Meanwhile these same people (not really, I suspect ERCA is someone's pet project who just really likes cannons) have a guided missile system capable of greater accuracy and deadlier payload available, in the form of GMLRS-ER, coming online at the end of this decade and PrSM which will overmatch any existing Chinese or Russian tactical ballistic missile system barring Iskander.

This is what happens when acquisition isn't overseen by a General Staff with a coherent idea of how to fight the next wars.

 

[Scott Kenny]

If they can fit something like Damocles inside a 155mm shell it might be useful for counter-battery, but only in a very limited fashion. PGMs are expensive. Even then, rocket artillery is usually preferred for counter-battery, because it can fire a massive amount of ordnance rapidly and displace, and expect that ordnance to hit a target quickly and near simultaneously. This is harder with a cannon but a wide area search system like Damocles could work. Might need to nix the EFP for a Thales Fury or something though.

Damocles?

Only if you think nuclear war will somehow end all life or whatever. The more likely outcome is that anyone hit with a substantial amount of nuclear weapons just turns into Russia in the 1990's, or Japan in the 1950's, or something similar, and becomes a regional power pretty much permanently. It would still be able to sling military muscle in the near abroad but little else.

No, using nukes will just end your country, hence Mutually Assured Destruction.

No, it would have required the U.S. to not purchase AFAPs or W70s and rely solely on the conventional cassette warheads of these weapons. Considering the U.S. did exactly that with MGM-140 and the 155mm guns (W82) in the Reagan administration, this is not impossible in the slightest, so something changed with American calculus in the 1980's to make it decide tactical nuclear weapons were infeasible.

Probably the issue described by Tom Clancy in Red Storm Rising, that nukes require Politburo approval for use and by the time a request goes up to the Politburo for approval and that approval makes its way back down to the Corps commander the tactical opportunity has gone away.

Which means you need to delegate the release of nuclear weapons down to the Corps to Army commander.

Democratic armies are uniquely vulnerable to attack through intelligence pathways, though, as ERCA proves: its entire genesis relies on DIA being duped by the Russians and Chinese into thinking they have better guns than they actually do. To a lesser extent, the tactical nuclear weapons dismissal by Reagan in the 1980's is another attack by a foreign power through an intelligence pathway.

ERCA has no practical military purposes, except that it was designed to outshoot the supposed manufacturer-provided performances of the PLZ-52 and the Koalitsiya-SV, two guns that either do not approach what they claim in reality (due to lack of specialized shells) or do not exist in sizeable quantity. It does this by a very inefficient mechanism: a massive powder charge and high muzzle velocity, when a subcaliber round fired from an L/52 (as, allegedly, "demonstrated" by the PLAGF) can do the same job.

The idea that PLZ-52 is just another defense contractor bigging up their brochure with nonsense that has no practical value, and Koalitsiya-SV will remain an unmanufactured prototype well into the next decade, simply did not cross these people's minds.

Yet that is the threat ERCA is designed to "meet". The idea that they could simply purchase an off-the-shell M109I7 or Pzh 2000 and slap it into an M109 also did not cross these people's minds, because they "need" to "overmatch" these mostly imaginary threats.

Meanwhile these same people (not really, I suspect ERCA is someone's pet project who just really likes cannons) have a guided missile system capable of greater accuracy and deadlier payload available, in the form of GMLRS-ER, coming online at the end of this decade and PrSM which will overmatch any existing Chinese or Russian tactical ballistic missile system barring Iskander.

This is what happens when acquisition isn't overseen by a General Staff with a coherent idea of how to fight the next wars.

See also the creation of the 6.8x51mm small arms round. And the choice of the SIG round which was the most expensive and complex per round and required the most engineering due to the insane pressures necessary to get a 140gr bullet to 3000+fps out of a 13" barrel.

Nevermind that many of the generals joined up after Desert Storm, if not after 9/11, so have never fought in a conventional full sized war.

 

[yeetmahboi]

Reflecting on Kat Tsun's comment on switching ERCA to nuke-deployment only.

The use of a corps-level tactical artillery system sounds promising in theory - it fills a role that doesn't require expensive TBMs and can be used semi-forward deployed, so something around 150-200km behind the FEBA that can respond to a commander's request for a relatively fast and plentiful WMD asset to knock out large concentrations or structures. I don't neccesarily disagree with such an opinion even considering the dangers of tacnukes, because ERCA as a theatre artillery will have to make its cost worth. 155mm prefragmented rounds is too small for that, and BAI is consuming.
Historical long range guns like the M107 were used conventionally in Vietnam because the 105mm and 155mm tubes back then were not suitable for covering the entirety of South Vietnam. A gun that can reached out 40km in such an environment is certainly a godsend. Distributed artillery batteries neccesitate LRPF tubes, which is the same exact situation the US Army is expecting, and has faced. The only problem is that Vietnam is smaller than Iraq or Eastern Europe, and the US Army had a lot of troops back then. M107 was a a corps asset while XM1299 is/would be a divisional one intended for use alongside updated M109A7 units under PenDiv. So entirely different roles and compositions.
ERCA, as it seems, sacrifices the ability to use legacy stocks in order to substantially boost its reach. If it is only use as a high level asset spitting out 155mm tacnuke LRLAP-style shells, and it stocks numbered in the thousands at most, then that would be entirely fine because a couple thousand tacnukes is a reasonable amount for warfighting, and doesn't complicate logistics. Have Nammo split into a different division dedicated entirely to developing nuclear artillery?
Regardless it's all paper talk because I doubt the current Anglosphere climate would even allow rebuilding stockpiles of strategic let alone tactical nuclear weapons. ERCA either evolves ( or, devolves) to be capable of using standard 155mm, or gets cancelled in favor of buying M109A7s upgraded with L52 barrels. If its the latter ( I have my doubts on whether could Rheinmetall L52s reach the range required for ERCA), give the US Army armed, fix-wing UAV CAS/BAI, something along the line of Mojave, but that would violate Key West anyway. Or GMLRS-ER, but that would be too logical to buy.

The idea that PLZ-52 is just another defense contractor bigging up their brochure with nonsense that has no practical value, and Koalitsiya-SV will remain an unmanufactured prototype well into the next decade, simply did not cross these people's minds.

PLZ-52 is actually real, and has already been updated into the PLZ-05B version, which is apparently in LRIP rn. However US-PLA artillery dual is immaterial unless the Pentagon wants to downside a couple of brigades for a "legit" reason.

 

[Scott Kenny]

Reflecting on Kat Tsun's comment on switching ERCA to nuke-deployment only.

The use of a corps-level tactical artillery system sounds promising in theory - it fills a role that doesn't require expensive TBMs and can be used semi-forward deployed, so something around 150-200km behind the FEBA that can respond to a commander's request for a relatively fast and plentiful WMD asset to knock out large concentrations or structures. I don't neccesarily disagree with such an opinion even considering the dangers of tacnukes, because ERCA as a theatre artillery will have to make its cost worth. 155mm prefragmented rounds is too small for that, and BAI is consuming.
Historical long range guns like the M107 were used conventionally in Vietnam because the 105mm and 155mm tubes back then were not suitable for covering the entirety of South Vietnam. A gun that can reached out 40km in such an environment is certainly a godsend. Distributed artillery batteries neccesitate LRPF tubes, which is the same exact situation the US Army is expecting, and has faced. The only problem is that Vietnam is smaller than Iraq or Eastern Europe, and the US Army had a lot of troops back then. M107 was a a corps asset while XM1299 is/would be a divisional one intended for use alongside updated M109A7 units under PenDiv. So entirely different roles and compositions.
ERCA, as it seems, sacrifices the ability to use legacy stocks in order to substantially boost its reach. If it is only use as a high level asset spitting out 155mm tacnuke LRLAP-style shells, and it stocks numbered in the thousands at most, then that would be entirely fine because a couple thousand tacnukes is a reasonable amount for warfighting, and doesn't complicate logistics. Have Nammo split into a different division dedicated entirely to developing nuclear artillery?
Regardless it's all paper talk because I doubt the current Anglosphere climate would even allow rebuilding stockpiles of strategic let alone tactical nuclear weapons.

There have been several talks, including a pretty major congressional report, about increasing the size of the nuclear stockpile.

Which will also happily provide a crapton of DU for ammunition.

ERCA either evolves ( or, devolves) to be capable of using standard 155mm, or gets cancelled in favor of buying M109A7s upgraded with L52 barrels. If its the latter ( I have my doubts on whether could Rheinmetall L52s reach the range required for ERCA), give the US Army armed, fix-wing UAV CAS/BAI, something along the line of Mojave, but that would violate Key West anyway. Or GMLRS-ER, but that would be too logical to buy.

The USAF didn't scream too loudly when the Army insisted on adding Hellfire capabilities to their MQ-1C Grey Eagles, so I think that the Army could buy Mojaves and get away with it. Especially if they only armed the Mojaves with Hellfires and APKWS, no JDAMs.

 

[jsport]

https://twitter.com/x/status/1529081399525113856

View: https://twitter.com/lfx160219/status/1529081399525113856

https://twitter.com/x/status/1308600382118002688

View: https://twitter.com/lfx160219/status/1308600382118002688

South Korea and a 400km rg gun. They most likely the PLA is not joking around about superguns.

 

[Kat Tsun]

ERCA, as it seems, sacrifices the ability to use legacy stocks in order to substantially boost its reach

Yeah, it can do that fine. The issue is this wasn't what the Army told DOD back in 2018 while they were building a case for ERCA.

It's one of several reasons why ERCA will get canceled next year, when it comes up for review in FY25. ERCA is looking less like a simple upgrade and more like a major procurement program. Two alternatives to being canceled exist, either ERCA is upgraded to a major program, or ERCA gets a waiver or two for a year extension to FY26 or FY27.

Neither are likely given USD A&S's current hostility to spending money.

PLZ-52 is actually real, and has already been updated into the PLZ-05B version, which is apparently in LRIP rn. However US-PLA artillery dual is immaterial unless the Pentagon wants to downside a couple of brigades for a "legit" reason.

It exists in a sense that it's a gun that can equivocate any other 52-caliber cannon.

It's not realistically firing 100 km shells using anything comparable to the normal stocks of PLA 152mm ammo, unless it's firing either subcaliber rounds or highly reduced payload using ramjet shells or large folding lifting wings, which will reduce the lethality of the munition. The supposed accuracy of WS-35 isn't very impressive, either, being comparable to legacy ammunition at 100 km (~40 meters), which suggests it isn't terminally guided. Which means you will need to fire more rounds per target and each round is more expensive than ordinary ammunition, and I'm not sure the PRC can actually afford this, even accounting for its comparative advantages in manufacturing.

Rockets are superior for long range fire, even dumb munitions or PGK kits, because they have higher payload fractions. Especially at range.

XM1155 will offer similar performance, with terminal guidance at range, which will likely make it more lethal per dollar than the WS-35 at the end of the day. If WS-35 gets a terminal guidance kit it will be a pretty serious weapon, though not anymore than XM1155, and that is perhaps in the future. They may be neck and neck, or America may be able to pull a super WS-35 out of its sleeve, but the PLA's rocket launchers are still going to be the main threat at ranges in excess of 50-70 km for the foreseeable future.

Ultimately GMLRS-ER will end up doing ERCA's job (150 km), maybe combined with normal L39 or L52 guns with XM1155s (100 km), and the former to be procured in huge quantities in all likelihood. It's about to enter mass production, Finland has purchased it, and there's a strong push for it. GMLRS was highly affordable (~60,000 rounds produced) and seems to be quite lethal at range to boot, so it isn't clear why GMLRS-ER won't be similarly affordable.

60,000 rounds isn't a lot compared to artillery shells, but compared to Tochkas and 9M542, it is a lot. Perhaps the PRC has more ammo though, I don't know. It wouldn't be too surprising tbf.

 

[yeetmahboi]

It's not realistically firing 100 km shells using anything comparable to the normal stocks of PLA 152mm ammo

PLZ-52/05 in PLAGF service use 155mm shells, courtesy of Gerald Bull.
Btw PLZ-05's barrel lenght has no relevance on the use of WS-35 and similar extended-range shells in PLA inventory. We did see it being fired from a normal PLZ-05 after all.
The thing is that WS-35 has 2 variant: the 1620mm long version wide 100km range and the 910 long version that has a max range of 40km according to brochure:

The problem is that the 100km version has been widely disregarded as a myth by actually serious PLA watchers! So lets end the PLA debacle here and move back to topic.

 

[Cordy]

Breaking Defense write up October 20, Army service acquisition head Doug Bush looking at the ERCA program, both cannon and rounds and the many options in relation for funding in the FY25 budget. The 30-foot 58-caliber gun tube M109A7 with its supercharged propellant with the goal to fire 155 mm rounds out to 70 km, an increase from the current max range of up to 30 km, which has encountered technical challanges during live fire testing, including excessive wear and tear on the cannon. Also the wheeled versus towed artillery debate and looking at using a 120 mm mortars for lighter formations. Bush pointed towards what he said were several options for a new 52-caliber cannon including BAE Systems’ M109-52 prototype with the Rheinmetall L52 main gun and integrates in a M109A7.

Another possible option in delaying the cannon and accelerating progress with the new XM1155 155 mm rounds, the BAE sub-caliber vs the Boeing/ Nammo ramjet, Raytheon has withdrawn from the competition.

BAE believes they’ve beaten Boeing for the M109 record “We believe we did. Several times over. And we believe we’ve done it guided and they have not. // Our XM1155-SC test in April 2023 was fired from a tactically representative M109A6 (39 caliber) using MACS [modular artillery charge system] Zone 5 and guided to and impacted the target. To the best of our knowledge, the XM1155-SC went further than any round fired from an M109 // XM1155-SC is currently and will remain compatible with existing Army validated and tested propellant charges designed to meet barrel wear and firing rate requirements.”

Boeing said range limitations prevented the company’s offering from going its full distance for the test announced at AUSA and also highlighted the benefits of ramjet technology for reducing wear and tear on a platform, the logic being that “when heavy charges are used to boost traditional or sub-caliber munitions to achieve range increases, it can damage and reduce the lifecycle of cannons,” as opposed to a ramjet design “that requires much less charge” as well as the “form factor” of a ramjet-powered shell that “gives it speed advantages that reduce time to target.

Shooting for the moon: Army’s 2025 budget to reflect artillery revamp - Breaking Defense

“If the… 58-cal cannon solution can't deliver on a timeline we want, what are the other options? That can be munitions…new munitions with old cannons and it can be different cannons,” said Army acquisition head Doug Bush.

breakingdefense.com

 

[kqcke for you]

But wasn't xm1155 meant for use of the larger Charge ? So beoing says like drop it so this gun can work with old rounds but then you could just Buy a L52 from Rheinmetall. Maybe even L/52A1 or L/60 when the time comes.

 

[Kat Tsun]

But wasn't xm1155 meant for use of the larger Charge ? So beoing says like drop it so this gun can work with old rounds but then you could just Buy a L52 from Rheinmetall. Maybe even L/52A1 or L/60 when the time comes.

XM1155 is just a ramjet powered shell. The only difference between the ERCA/60 caliber version and a conventional L/39 or L/52 would be the driving band. It's only one-ways compatible, in that older cannons can fire the high pressure gun's rounds, but not the reverse. Kind of like .223 and 5.56mm chambers.

L/60 itself just seems to be Rheinmetall's own version of ERCA, so I don't know if it will go anywhere, tbh.

It has a muzzle velocity of 1,145 m/s, which is fairly close to ERCA/XM282 (it's probably faster, unsurprisingly), and uses some similar non-copper driving band, and has an operating pressure of around 56,000 psi. Presumably it uses nickel, since in Armaments Center tests it was the least degraded band-type, and thus the most likely to be used in any novel driving band for shooting past 900-1,000 m/s or so:






It could also be stainless steel, though, as that would be a cheaper and less strategic a material. For that matter, ERCA might use stainless steel, but even stainless can rust and that's bad juju for storage. I guess production ERCA rounds could be iron driving bands since that is actually the best in terms of general wear and economics, with the obvious and really only downside being iron would rust, but more than likely it's going to be nickel due to those same storage concerns.

Nickel was preferred during the 90's tests though, both because it had similar performance to stainless and cast iron, but was corrosion proof.

From the test data and the observations made on the recovered hardware, the silicon-bronze
rotating bands did not survive the gun firing. This confirmed some of the earlier metallurgical bend
tests that the Materials and Structures Branch at ARDEC had conducted during preliminary welding
experiments. Although the earlier welding experiments indicated that the silicone-bronze may not be
well bonded to the projectile, it was speculated that its bond had just enough strength to survive the
firing. Thus, silicon-bronze was not totally eliminated from the candidate rotating band materials list
early on so that its bond and welding parameters could be evaluated via a live-firing. The results of
the firing also indicated that the CPC BTPs with the copper rotating bands were comparable to the
M864 projectiles. Thus, as a measure of performance, the standard copper band of the M864
projectile is used for future analyses.

Based on the ARDEC structural test results, a firing at Yuma Proving Ground (YPG), Yuma,
AZ was conducted in order to evaluate the rotating band materials in a 58 caliber gun. This firing
was completed in November of 1997. It consisted of using an XM282, 58 caliber, high contractile
chrome cannon with a 1,700-in.3 chamber. The tube rifling twist was 1 in 22.5, and the propelling
charge used was an XM230 zone 6 conditioned at ambient temperatures. Along with three M864
projectiles used as comparison rounds, a total of 14 CPC BTPs were fired. The 14 CPC BTPs
consisted of rotating bands manufactured out of copper, silicon-bronze, soft iron, nickel, MONEL®,
and stainless steel. All of the test projectiles were fitted with standard M864 obturators. The results
of this test are summarized in table 5 and photographs of some of the recovered hardware are
shown in figures 8 and 9.

(...)

It is interesting to note that the nickel band slightly outperformed the stainless steel. This is
apparent by examining the tabulated average wear measurements shown in table 7. As the data is
compared to the predicted Sandia 1-D wear model, it is noted that the stainless steel should have
performed similarly to nickel. Reasons for the differences may be due to the changes in the
stainless steel material properties from welding and fabrication in addition to the limitations of the

The predicted wear measurements shown in table 7 were generated based on pressure
profiles not used in the actual gun firing. Due to this difference in pressure profiles, the correlation of
predicted versus actual rotating band wear could be slightly skewed. Additional factors affecting the
percentage differences in the predicted data versus the actual data are due to the fact that wear is
three-dimensional and contingent upon surface conditions of the gun tube. Nevertheless, the
generated data can still be somewhat correlated to expected wear values, and the Sandia 1-D wear
model has been and is currently used as a very useful design tool.

Emphasis mine.

https://apps.dtic.mil/sti/pdfs/ADA620119.pdf

That said, not sure there's much a market for 60-caliber or ERCA-type cannons given the hypothesized threat that demanded the 80-100 km range isn't real, either. Most likely outcome is a general shift by the U.S. Army to international L/52 standard (probably based on the Pzh 2000) mated to a M109A7 PIM hull and possible adoption of powered flight shells for real extended range use by these types of cannons.

The only potential use case L/60 could offer is the ability to fire pre-existing rounds at 60+ kilometers...



...which it can't actually do, because it has the same "problem" ERCA does in that it demands a more resilient driving band:

A mid-term solution is offered by the L52A1 gun, which is an optimisation of the currently available gun installed on the PzH 2000, which can be qualified in shorter times compared to a fully new weapon. It uses the same barrel, the same breech and the same sealing system, however it has a bigger chamber volume and the chamber pressure is increased

The long term solution obviously comes with the L60 gun and new projectiles, which are being developed to answer the aforementioned Future system Medium range indirect fire programme which requirements calls for a 75 km range with conventional ammunition. “As this figure is for non guided ammunition, we added some range to compensate course correction fuses,” Dr. von Hörsten explains. The 82 km range will be reached using a V-LAP projectile, which EDR On-Line understood being a new development of currently available rounds that will maintain the same outer dimensions and weight, 43.5 kg, to be JMOU compatible, but will be hardened to accept higher pressure levels.

“The V-LAP carries around 4 kg of explosive, however we are working on pre-fragmented designs that will increase lethality,” he added. As part of its ammunition development programme Rheinmetall is also working on a new driving band, which was tested in 2021 shooting from a PzH 2000, using modified charges. The charge system for the L60 will adopt a stub case, to deal with higher chamber pressures, and the primer will be screwed into the stub case and not located in the breech. reaching a muzzle velocity of 1,144 m/s. First trials are expected to take place in early 2023.

Emphasis mine, again.

Indirect fires: Rheinmetall details its latest solutions - EDR Magazine

Rheinmetall’s roadmap in the field of indirect fires: increasing ranges exploiting new guns, new projectiles and new charges. EDR reports.

www.edrmagazine.eu

It will run into the same issues and stumble on the same problems, most likely. Rocket launchers seem to be ideal for firing at beyond 60-70 kilometers, though. Maybe the U.S. Marines are onto something?

Anyway this big post is mostly just because I found the paper on DTIC that talked about nickel driving bands being very good for high pressure gun applications again.

 

[Scott Kenny]

XM1155 is just a ramjet powered shell. The only difference between the ERCA/60 caliber version and a conventional L/39 or L/52 would be the driving band. It's only one-ways compatible, in that older cannons can fire the high pressure gun's rounds, but not the reverse. Kind of like .223 and 5.56mm chambers.

That's not a really good comparison, the only difference there is Overall Length and therefore lede distance, and it only shows up in match .223 bolt action rifles. The better comparison would be 7.65 Parabellum and 7.62 Tokarev. The Tok rounds are enough higher energy to be actively dangerous to any gun chambered in Parabellum.

Anyway this big post is mostly just because I found the paper on DTIC that talked about nickel driving bands being very good for high pressure gun applications again.

Link, please?

 

[Kat Tsun]

That's not a really good comparison, the only difference there is Overall Length and therefore lede distance, and it only shows up in match .223 bolt action rifles

Firing 5.56mm in a .223 chamber can cause damage, yes. Likewise, you can fire a copper banded round through a 58-caliber or 60-caliber tube if you're willing to accept the shell might cause the tube to detonate after a couple hundred rounds instead of a couple thousand.

Link, please?

The link is literally in the post. The things I've referenced the past few pages, like ERCA's program schedule slippage and upcoming MTA review, are from GAO reports and such that I've also been linking to...

Army moving ERCA, LTAMDS from rapid prototyping to major capability acquisition - Breaking Defense

The Army decided to transition ERCA after DoD denied providing the service with a wavier to keep the program under the rapid prototyping umbrella, GAO said.

breakingdefense.com

Currently the Army is going to attempt a Major Tier Acquisition case for both ERCA and LTAMDS. It remains to be seen how well this will be funded, or approved, by DOD and the Congress, since the FY25 budget won't be submitted until February.

It may be canceled. It has a high (greater than even) chance of this. USD A&S has little patience for busted Army programs because they don't want a repeat of Comanche, JAGM's various incarnations, LOSAT, CKEM, Future Combat Systems, or whatever else you can name. It may also be upgraded to Major Tier Acquisition, or granted an exception to the 5-year Middle Tier Acquisition pathway, in descending orders of likelihood.

The most likely outcome is it will either be canceled sometime next year, when the Congress or DOD don't approve the budget, or it will be canceled in 2-3 years time when it still ends up busted or GMLRS-ER enters mass production. If war happens before then it may be accelerated to mass production. Maybe.

So ERCA may yet still be developed, but it will take several years to work out the kinks I imagine. The autoloader won't even be ready until 2025 (a pretty important piece!) and the cannon may yet have more trouble down the road during its development than just the new driving bands for shells and barrel life problems:

LRPF: Army Missiles, Cannon Face Big Tests In ’21 - Breaking Defense

Weapons from hypersonics to howitzers have key deadlines to meet next year to keep to the Army’s ambitious timeline, Lt. Gen. Neil Thurgood and Brig. Gen. John Rafferty tell Breaking Defense.

breakingdefense.com

The Army already has a full-up working prototype of the tank-like ERCA, an armored self-propelled howitzer, and the weapon played a starring role in this year’s recently concluded Project Convergence wargames. But there are plenty of details and glitches to work out before ERCA enters service in 2023.

In order to achieve double the range of existing Army howitzers, Rafferty explained, ERCA uses an extra-long barrel and new high-powered propellant, all of which puts a lot of stress on the weapon. “Barrel wear, that’s a real concern,” he told me. “We want to find the sweet spot” that gives the best balance between range and barrel life.

One crucial component is called the rotating band, a thin metal sleeve that fits between the barrel and the projectile. The rotating bands used to date weren’t tough enough, so the Army has ordered a harder version, which will be on hand by the end of this year for use in test shots next year.

Since it's basically a rifled tank gun at this point (high pressure, obturating stub case similar to a 120mm, and rifled), it presumably has pretty bad barrel life. Some of the early L7s (and M68s?) had tube lives as low as 200 rounds. 2A46 has a lifespan of 350 EFCs in the T-72 initially.

Considering the M777 has an EFC >2,000 rounds with the M203A1 and M284 is around 1,000 or 1,500, it's gotta pretty bad to be considering tube life "a real concern" tbh. This is compared to Pzh 2000's 4,500 EFCs, too, which uses better steel in the barrel. I suppose ERCA could just be using older metallurgy or something, so maybe an improved tube will increase the life, but right now they're XM282 tubes.

Tack "new tube" onto the list of backlogged issues like the autoloader, and we might see an IOT&E in 2026 at this rate. If any new tube requires new gun motors, and a rebalanced turret, add another year or two onto that, just in time for GMLRS-ER to eat its lunch. ERCA is basically running into walls of problems since 2021 or so, and while they tried to blame COVID, the reality is more like the XM282 is just a finicky SOB to weaponize.

DA is just now discovering why their now-retired (or dead) bosses 30 years ago, back when DA's brass were 2LTs in the Artillery Branch and freshly gearing up to invade Bosnia, didn't bother putting it into the Paladin.

 

[kqcke for you]

XM1155 is just a ramjet powered shell.

No its Not? Boeings /Nammo offer is and they say because it is they don't need as high Velocitys so i understand they want / can achieve IT without the Supercharge which makes the whole gun useless as taking an L/52 from Rheinmetall would be cheaper for them.

The only difference between the ERCA/60 caliber version and a conventional L/39 or L/52 would be the driving band.

But they say say need less Velocity which would be less pressure so just maybe no new Drive Band and then again no point in ERCA.

Or thats how i see and understand it.

 

[Kat Tsun]

But they say say need less Velocity which would be less pressure so just maybe no new Drive Band and then again no point in ERCA.

Which is why it's the better option, yes. As it stands, ERCA is only useful for pummeling Soviet BM-27s with M864s.

 

[A Tentative Fleet Plan]

The Rheinmetall 60-calibre 155mm does have a smaller chamber than the XM282/XM907, 25-litres (same as the G6-52 Extended Range) compared to 28-litres.

Most 52-calibre 155mm have a chamber volume of 23-litres.

 

[MadRat]

In today's world you cannot manage with falling behind in sheer volume for the sake of novelty. Its a balancing act to get it right. Ultimately we need to maneuver in such a way that the enemy get stuck holding steady in kill boxes when rounds go up. They have other platforms that can pound them while they are isolated or on the move. You have to be able to shoot and scoot when they aren't. So, yes, barrel life is very important.

 

[sp_mm]

The Rheinmetall 60-calibre 155mm does have a smaller chamber than the XM282/XM907, 25-litres (same as the G6-52 Extended Range) compared to 28-litres.

Most 52-calibre 155mm have a chamber volume of 23-litres.

Rheinmetall's 155 mm L/60 gun has a 29 litre chamber, not a 25 litre chamber.

 

[Scott Kenny]

Firing 5.56mm in a .223 chamber can cause damage, yes. Likewise, you can fire a copper banded round through a 58-caliber or 60-caliber tube if you're willing to accept the shell might cause the tube to detonate after a couple hundred rounds instead of a couple thousand.

Only in a very specific case, with a known extra short lede chamber. Kimber .223 bolt action rifles, specifically, and it has to do with how the short lede can result in setting the bullet back in the case leading to egregious overpressure, pierced primers, and blowtorching out the firing pin channel in the bolt.

As opposed to a very general case of putting a 7.62 Tokarev into a 7.63 Luger being likely to blow up the gun in your hand.

Currently the Army is going to attempt a Major Tier Acquisition case for both ERCA and LTAMDS. It remains to be seen how well this will be funded, or approved, by DOD and the Congress, since the FY25 budget won't be submitted until February.

I do hope that the LTAMDS gets completed and deployed.

Since ERCA was not the CONOPS I thought it was, I don't see the point of it specifically. I just want every M109 to have a 52-60cal barrel and we'll call it done. Set muzzle velocity to 945m/s at max charge, so you can still use copper driving bands safely.

Since it's basically a rifled tank gun at this point (high pressure, obturating stub case similar to a 120mm, and rifled), it presumably has pretty bad barrel life. Some of the early L7s (and M68s?) had tube lives as low as 200 rounds. 2A46 has a lifespan of 350 EFCs in the T-72 initially.

Considering the M777 has an EFC >2,000 rounds with the M203A1 and M284 is around 1,000 or 1,500, it's gotta pretty bad to be considering tube life "a real concern" tbh. This is compared to Pzh 2000's 4,500 EFCs, too, which uses better steel in the barrel. I suppose ERCA could just be using older metallurgy or something, so maybe an improved tube will increase the life, but right now they're XM282 tubes.

Tack "new tube" onto the list of backlogged issues like the autoloader, and we might see an IOT&E in 2026 at this rate. If any new tube requires new gun motors, and a rebalanced turret, add another year or two onto that, just in time for GMLRS-ER to eat its lunch. ERCA is basically running into walls of problems since 2021 or so, and while they tried to blame COVID, the reality is more like the XM282 is just a finicky SOB to weaponize.

DA is just now discovering why their now-retired (or dead) bosses 30 years ago, back when DA's brass were 2LTs in the Artillery Branch and freshly gearing up to invade Bosnia, didn't bother putting it into the Paladin.

Note that Ukrainian gunners were complaining about shooting out their donated PzH2000s in pretty short order, even with that 4500rd EFC rating. I suspect that they were shooting 30 rounds in 5 minutes, relocating for 5 min, shooting another 30 rounds, repeat; so they were averaging 3rpm all day long. And that means you hit 4500 rounds fired in 25 hours.

 

[Kat Tsun]

Since ERCA was not the CONOPS I thought it was, I don't see the point of it specifically. I just want every M109 to have a 52-60cal barrel and we'll call it done.

I think originally it was supposed to be the actual M109A8 but that was before they discovered the turret problems. ERCA is essentially a new build turret, instead of a drop-in replacement, and so that increases the cost. This pushes ERCA up to a Corps asset for long range fires instead, to complement the HIMARS and M270s already there, and while it still has some value it's much less than it would be.

The Army's "ideal" when it eventually writes it down on paper will probably be M109L52 with a few battalions of ERCA to give the Corps commander a muscular suppression ability. In other words, we are returning to the past, with ERCA cosplaying as the M107/M110, and GMLRS-ER as the MGM-52.

Set muzzle velocity to 945m/s at max charge, so you can still use copper driving bands safely.

Honestly, probably not, but DA's reasons for using copper are historically rooted: Americans weld the driving bands onto the shell.

Other countries use different driving band materials and construction methods that can handle the L/52 muzzle velocities just fine. Theoretically, you could additive manufacture/laser sinter a porous iron band onto the shell, for instance, but this would require major re-investment into the howitzer industrial base. It would also hurt the barrel without a copper or brass coat or leading edge.

I believe the Germans swage their bands on, and during the last war, the Nazis used bimetallic copper (or brass) and cast iron bands.

https://apps.dtic.mil/sti/tr/pdf/ADA376695.pdf

After copper got restricted due to Allied bombers and blockades, they switched to full cast iron, with predictably worse barrel lives, but the bimetallic bands are suitable for "medium velocity" (i.e. ERCA and L/60) cannons in general. Some really big guns had rifling directly engraved into the shell, like old rifled cannons, during the war too.

Of course the optimal future is to simply eliminate rifling and fire a self guided munition with moving fins/canards from a smoothbore.

 

[Scott Kenny]

I think originally it was supposed to be the actual M109A8 but that was before they discovered the turret problems. ERCA is essentially a new build turret, instead of a drop-in replacement, and so that increases the cost. This pushes ERCA up to a Corps asset for long range fires instead, to complement the HIMARS and M270s already there, and while it still has some value it's much less than it would be.

The Army's "ideal" when it eventually writes it down on paper will probably be M109L52 with a few battalions of ERCA to give the Corps commander a muscular suppression ability. In other words, we are returning to the past, with ERCA cosplaying as the M107/M110, and GMLRS-ER as the MGM-52.

Nothing wrong with that, it was a pretty functional system.

Honestly, probably not, but DA's reasons for using copper are historically rooted: Americans weld the driving bands onto the shell.

Other countries use different driving band materials and construction methods that can handle the L/52 muzzle velocities just fine. Theoretically, you could additive manufacture/laser sinter a porous iron band onto the shell, for instance, but this would require major re-investment into the howitzer industrial base. It would also hurt the barrel without a copper or brass coat or leading edge.

I believe the Germans swage their bands on, and during the last war, the Nazis used bimetallic copper (or brass) and cast iron bands.

https://apps.dtic.mil/sti/tr/pdf/ADA376695.pdf

After copper got restricted due to Allied bombers and blockades, they switched to full cast iron, with predictably worse barrel lives, but the bimetallic bands are suitable for "medium velocity" (i.e. ERCA and L/60) cannons in general. Some really big guns had rifling directly engraved into the shell, like old rifled cannons, during the war too.

Of course the optimal future is to simply eliminate rifling and fire a self guided munition with moving fins/canards from a smoothbore.

Sure, if you don't mind needing to build up a dedicated stock of ammunition for that gun alone. There's a reason the US has basically standardized on 155mm tubes, towed or self-propelled.

 

[Kat Tsun]

Nothing wrong with that, it was a pretty functional system.

Except it wasn't what Armaments Center or DA said they would be providing to DOD. You don't really promise to build a public pool, and then actually build a casino, even if you get more profit at the end of the day.

Sure, if you don't mind needing to build up a dedicated stock of ammunition for that gun alone.

...which will be required by ERCA anyway...

There's a reason the US has basically standardized on 155mm tubes, towed or self-propelled.

Because it adopted French 155mm guns in the 1910s?

There's also a reason XM282 wasn't put into Paladin, either.

Do you see how the pieces fall together? The historic choices made by DA over the past, uh, literal 100 years or so have led to ERCA being a failure. Primarily because it was supposed to predicate itself on that history.

By not being backwards compatible with older munitions stocks, by not being routinely expected to use the MACS (supercharge is a MACS 7 equivalent) thus needing a new-type autoloader, and by requiring the use of a different driving band material to accommodate American shell manufacturing capacities, ERCA has failed in its major business case it made to DOD back in 2018.

ERCA evidently must have pretty shaky military justifications because the normal route would be to say "we need to shoot at <70 kilometers> to counter <specific battlefield weapon/BM-27 Uragan/whatever> and keep it under constant threat of <suppression/harassing fires> using a cannon, because rocket launchers aren't great at that" or whatever. The threat can be totally made up and fake, like the WS-35, or the VRFWS's primary armor threat ("necessitating" the development of the 25mm M791 APDS around 1967 or so) or whatever.

Sure, this route has resulted in fistfights (or nearly so) in meetings between officers, but a fistfight is better than a legal spat, or nebulous finance turmoil as people scramble to assemble Powerpoints justifying their budget to DOD tbh. Settling your disputes regarding battlefield threats' veracity via fisticuffs in the boardroom is a time honored tradition, because it works. Scrambling to rebuild your business case after everything you promised falls through isn't, because it never really works.

If it can recover from this cascading spiral of "oops, we lied", it will turn out perfectly average, at least as far as 70 km cannons go.

 

[Scott Kenny]

...which will be required by ERCA anyway...

Which wasn't supposed to be required by ERCA.

Because it adopted French 155mm guns in the 1910s?

No, because there were immense logistical reasons to have all gun artillery as one caliber.

By not being backwards compatible with older munitions stocks, by not being routinely expected to use the MACS (supercharge is a MACS 7 equivalent), and by requiring the use of a different driving band material to accommodate American shell manufacturing capacities, ERCA has failed in its major business case it made to DOD back in 2018.

ERCA evidently must have pretty shaky military justifications because the normal route would be to say "we need to shoot at <70 kilometers> to counter <specific battlefield weapon> and keep it under constant threat of <suppression/harassing fires> using a cannon because rocket launchers aren't great at that". Sure, this route has resulted in fistfights in meetings between officers, but a fistfight is better than a legal spat, or nebulous finance turmoil as people scramble to assemble Powerpoints justifying their budget to DOD tbh.

If it can recover from this cascading spiral, it will probably turn out perfectly mediocre, at least as far as 70 km cannons go.

Love to have been a fly on the wall for that... Always fun to watch the ossifers tear each other apart when you're enlisted. "Didn't see a thing, sirs."

 

[Kat Tsun]

Which wasn't supposed to be required by ERCA.

No, it wasn't. The business case was partially built on backwards compatibility. We'll know how big of a deal it was if ERCA gets killed or not.

Between schedule slippage from the barrel wear problem and redesigns needed to fit in the M109A7 hull, and lack of backwards compatibility, I think ERCA is doomed. If they can make the case that ERCA is important regardless of backwards compatibility, it wouldn't have been a factor in the initial presentation, so it must be pretty weighty.

Armaments Center is probably vacillating between exasperated resignation and manic busywork about the whole ordeal right now.

No, because there were immense logistical reasons to have all gun artillery as one caliber.

There are immense (literally, weighty) logistical reasons to not go for 155mm in the Light Forces.

Arguably there's no industrial reason either, since a 105mm production line probably can't produce 155mm shells, and vice versa. You'd need different jigs, dies, tools, racks, etc; but there was actually a huge logistician pushback from 155mm in the Light Forces units anyway. It's why the 105mm M119 is still around in the 82nd and 101st Airborne and the 10th Mountain DS artillery battalions; M777 is for the GS battalions.

Armaments Center developed a plastic high capacity payload shell called LAP (lightweight artillery projectile) to address this in the 1990's using HICAP as a basis, back when the M777 was still the XM777. It never went anywhere because DA deferred to fund Crusader. LAP and XM777 would have given the same tonnage of 155mm twice the lethality of existing 105mm ICM shells.

That would mean half as many rounds to fire though, which means less suppression and fewer minutes of fire.

A similar Navy program, called Best Buy, was deferred for AGS too but I'm still waiting for the Wish.com Warhead to show in [dstl] documents.

Love to have been a fly on the wall for that... Always fun to watch the ossifers tear each other apart when you're enlisted. "Didn't see a thing, sirs."

https://apps.dtic.mil/sti/tr/pdf/ADA140367.pdf

Ctrl+F "fight".

 

[Scott Kenny]

No, it wasn't. The business case was partially built on backwards compatibility. We'll know how big of a deal it was if ERCA gets killed or not.

Between schedule slippage from the barrel wear problem and redesigns needed to fit in the M109A7 hull, and lack of backwards compatibility, I think ERCA is doomed. If they can make the case that ERCA is important regardless of backwards compatibility, it wouldn't have been a factor in the initial presentation, so it must be pretty weighty.

Armaments Center is probably vacillating between exasperated resignation and manic busywork about the whole ordeal right now.

Generally agree that ERCA as currently configured is doomed.

My next question would be about sticking the M777ER gun into an M109 as the general update, though that's not ERCA specifically so may need to go in a different thread.

There are immense (literally, weighty) logistical reasons to not go for 155mm in the Light Forces.

Arguably there's no industrial reason either, since a 105mm production line probably can't produce 155mm shells, and vice versa. You'd need different jigs, dies, tools, racks, etc; but there was actually a huge logistician pushback from 155mm in the Light Forces units anyway. It's why the 105mm M119 is still around in the 82nd and 101st Airborne and the 10th Mountain DS artillery battalions; M777 is for the GS battalions.

The advantage of 105mm is that it's also the caliber used in MPF, so at least the HE, Illum, and WP shells are the same between the two.

I'd kinda like to see what a sabot round would do out of an M119, but I expect it'd be slow. 105mm tank ammo has a lot more powder behind it than 105mm arty.

Armaments Center developed a plastic high capacity payload shell called LAP (lightweight artillery projectile) to address this in the 1990's using HICAP as a basis, back when the M777 was still the XM777. It never went anywhere because DA deferred to fund Crusader. LAP and XM777 would have given the same tonnage of 155mm twice the lethality of existing 105mm ICM shells.

That would mean half as many rounds to fire though, which means less suppression and fewer minutes of fire.

A similar Navy program, called Best Buy, was deferred for AGS too but I'm still waiting for the Wish.com Warhead to show in [dstl] documents.

Yeah, that's some stupidity talking. Sometimes what you need is sheer rate of fire, even if you are throwing ICM or a massive HE blast (not clear to me whether the LAP is HE or ICM)

https://apps.dtic.mil/sti/tr/pdf/ADA140367.pdf

Ctrl+F "fight".

Thank you!

 

[Kat Tsun]

Generally agree that ERCA as currently configured is doomed.

My next question would be about sticking the M777ER gun into an M109 as the general update, though that's not ERCA specifically so may need to go in a different thread.

Considering BAE/United Defense has already demonstrated integration of a modified Pzh 2000 combat module to the M109 hull...

The advantage of 105mm is that it's also the caliber used in MPF, so at least the HE, Illum, and WP shells are the same between the two.

You're not firing a 105mm howitzer round out of an M35. An M1130 projectile weighs almost as much as the entire M456 round.

I'd kinda like to see what a sabot round would do out of an M119, but I expect it'd be slow.

Poorly, but a direct fire HEAT round would work, which is what the 25-pdrs did. I don't know if the M67 HEAT is still around.

Yeah, that's some stupidity talking.

The actual calculation was the same rounds for twice the weight, but four times the lethality, at least according to JANUS modeling (presumably). For some reason I don't think I'd be able to replicate the same results in my copy of JANUS.

Sometimes what you need is sheer rate of fire, even if you are throwing ICM or a massive HE blast (not clear to me whether the LAP is HE or ICM)

"LAP" wasn't the actual designation. It was just called the "75 pound shell". "LAP" is just an abbreviation I used for the program as shorthand in that post. That said, yes that is why the DS battalions still have 105mm. Minutes of fire is more important for airborne forces than lethality.

 

[Scott Kenny]

Considering BAE/United Defense has already demonstrated integration of a modified Pzh 2000 combat module to the M109 hull...

Just seems odd to be using a ~30yo design to update the arty. M777ER seems to be a working system that is still backwards compatible with older ammunition.

You're not firing a 105mm howitzer round out of an M35. An M1130 projectile weighs almost as much as the entire M456 round.

Ah, explains a chunk of the velocity increase. Lighter shells and more powder.

But what I meant was that the same ammunition assembly line could probably make 105x617mm HE and 105x372mm HE, not necessarily that the tank guns could fire the arty shells. Might be nice if they could, but simply using parts of the same assembly line would be very useful.

Poorly, but a direct fire HEAT round would work, which is what the 25-pdrs did. I don't know if the M67 HEAT is still around.

There were switch settings on the M8 and M10 MPFs for HEAT, but that looks like it's the tank M456A2 (or possibly a newer one), not an arty-specific HEAT round.

The actual calculation was the same rounds for twice the weight, but four times the lethality, at least according to JANUS modeling (presumably). For some reason I don't think I'd be able to replicate the same results in my copy of JANUS.

Definitely would not have 4x the blast area. Granted that I'm using nuke modeling calculators, but doubling blast energy doesn't double blast radius.

"LAP" wasn't the actual designation. It was just called the "75 pound shell". "LAP" is just an abbreviation I used for the program as shorthand in that post. That said, yes that is why the DS battalions still have 105mm. Minutes of fire is more important for airborne forces than lethality.

Yes, but airborne are specialists. How many other leg infantry units have 105s versus 155s?

 

[Kat Tsun]

Definitely would not have 4x the blast area. Granted that I'm using nuke modeling calculators, but doubling blast energy doesn't double blast radius.

HICAP and 75-pound shell were DPICM cassette shells incorporating M80 grenades.

Yes, but airborne are specialists. How many other leg infantry units have 105s versus 155s?

...all of the infantry brigade combat teams have M119s. DA recently finished a major upgrade program for the M119 a few years ago.

The Stryker units have M777s instead of M119s for the most part, but they used to have M119s I believe.

 

[Scott Kenny]

HICAP and 75-pound shell were DPICM cassette shells incorporating M80 grenades.

Ah, okay, that makes more sense. I don't have a good free modeling program for multiple explosion coverage areas, do you have a recommendation?

...all of the infantry brigade combat teams have M119s. DA recently finished a major upgrade program for the M119 a few years ago.

The Stryker units have M777s instead of M119s for the most part, but they used to have M119s I believe.

Coulda sworn it was only a few of the infantry brigades had 105mm... And to my knowledge Strykers were always supposed to have M777s.

 

[MadRat]

If only you could grow a new smoothbore already in development to fire both extended range attack munitions out to 50-60km, but turn around and use a sabot round to crack tanks open at 5 clicks. Would probably need to aim for 130-140mm. Any new guns fit that description? That would solve two problems with one supply line and platform. Maybe it would even fit on an existing chassis they could convert to such duties.

 

[Scott Kenny]

If only you could grow a new smoothbore already in development to fire both extended range attack munitions out to 50-60km, but turn around and use a sabot round to crack tanks open at 5 clicks. Would probably need to aim for 130-140mm. Any new guns fit that description? That would solve two problems with one supply line and platform. Maybe it would even fit on an existing chassis they could convert to such duties.

Based on length of the LRLAP shell, as well as the 155mm artillery shells and 4.5" naval shells, you're likely to end up with a projectile that is the length of the complete sabot round for the long range work, that then gets a propellant stack the same length loaded behind it.

Which suggests that using such a setup halves the ammunition capacity in your ArtyTank, which is already hosed because of how big 130-140mm rounds are. ~25-31 rounds is what's been suggested for the 130mm, when 120mm tanks are holding at least 42.

Not to forget that an artillery tube needs a lot more elevation than a direct fire tank gun.

 

[Kat Tsun]

If only you could grow a new smoothbore already in development to fire both extended range attack munitions out to 50-60km, but turn around and use a sabot round to crack tanks open at 5 clicks. Would probably need to aim for 130-140mm. Any new guns fit that description? That would solve two problems with one supply line and platform. Maybe it would even fit on an existing chassis they could convert to such duties.

This is somewhat irrelevant to ERCA. XM282 was used because the prototype tubes were sitting at Watervliet. Middle Tier Acquisition precludes significant development time, that's the point of it. It turns out that ERCA will require, which is why the Army is seeking to upgrade it to a Major Capability Acquisition, and it remains to be seen if this will be approved. More than likely it will not be, as I suspect the Congress or DOD will say "LTAMDS and ERCA? Pick one," like they did with LOSAT and AGS, but we'll see.

 

[Scott Kenny]

This is somewhat irrelevant to ERCA. XM282 was used because the prototype tubes were sitting at Watervliet. Middle Tier Acquisition precludes significant development time, that's the point of it. It turns out that ERCA will require, which is why the Army is seeking to upgrade it to a Major Capability Acquisition, and it remains to be seen if this will be approved. More than likely it will not be, as I suspect the Congress or DOD will say "LTAMDS and ERCA? Pick one," like they did with LOSAT and AGS, but we'll see.

Agreed, and LTAMDS needs to be a higher priority.

 

[MadRat]

LTAMDS certainly isn't competing with ERCA.

They need to figure out ERCA ranges without a new platform. If they have to have a new chain of logistics and the barrel is short lived, then its a moot point, regardless if LTAMDS radar exists. If they want a high velocity gun then convert some MBTs into the role, where shell velocity is considerably higher by default. If the goal is counter-fire range at 50km then it shouldn't matter if it comes from 120mm or 155mm. But if your next generation MBT gun was 130-140mm then that is even better. The whole point of 155mm is to be standard within NATO. ERCA doesn't fit that.

 

[Kat Tsun]

LTAMDS certainly isn't competing with ERCA.

They are two programs moving from Middle Tier Acquisition to Major Capability Acquisition after encountering then-unanticipated (but not unknown) difficulties in development. They are directly competing, given DOD won't want to see MTA becoming a pipeline to the thing it was made to prevent i.e. endless money pits.

If the Army isn't told to "pick one", it will be surprising, to say the least.

The whole point of 155mm is to be standard within NATO.

That isn't true at all. Interoperability is different from a standard.

If there were a "standard", NATO countries would use the same tooling, processes, and materials. This is not the case.

I'm not sure if they even use the same charge systems or breech volumes at this point. DM72's low bound charge is smaller than MACS, while the M231 and M232 have the same volumes, but different propellants. At least when M109 was the dominant European NATO howitzer, it was clear.

ERCA doesn't fit that.

It would be able to fire German 155mm ammunition perfectly fine, assuming German guns still use the bimetallic iron-brass bands.

This is because NATO ammunition is not "standard" but merely "interoperable".

 

[bring_it_on]

LTAMDS certainly isn't competing with ERCA.

It is not. But one can always simply pick two MTA's with the Army and claim they will be forced to pick b/w one and the other and if it pans out that one does get cancelled we can claim we were right all along

 

[jsport]

. If they want a high velocity gun then convert some MBTs into the role, where shell velocity is considerably higher by default. If the goal is counter-fire range at 50km then it shouldn't matter if it comes from 120mm or 155mm. But if your next generation MBT gun was 130-140mm then that is even better.

Oh, as stated repeatly... the distinction between tank & SPH needs fade. Tank utilization rates on the current Ukr front displays direct tank on tank incidences are rare whereas tank gun for indirect fire is prevalent.