Let me see if I'm following all this correctly. The initial concept was a 70s/80s answer to the Air Force, (we will run out of missiles long before they run out of tanks) Fulda Gap problem. A "fighter" armed with a high-power recoilless or low-recoil cannon was proposed which showed that such a concept could carry around 5 times as many usable rounds for such missions than assuming a standard missile lead-out. (The cited pdf comparison chart BTW I note compares the gun/cannon round to Air Intercept Missiles rather than ground targets warheads, but the text indicates use against ground targets. I will note that the inference of usability against air-to-air targets is apt since the flechette cloud described is a similar kill system to the AIM) The suggested "Cannon-Fighter" would use an integral cannon to launch many separate rounds that would use added propulsion and guidance to allow more and multiple engagement and kills per sortie.
I'm guessing this was split off a separate thread since it references "6th Generation Fighter" posts, with the "OP" having brought up the concept as having possible utility towards that goal. The premise would seem to be the utility over "bomb/missile-truck" configured current generation fighters due to an ability to carry more 'warheads' being able to be delivered from a longer 'stand-off' range' per sortie. On the opposition side I'm noting protests over the applicability to various missions, (BVR-A2A, hardened target, anti-tank/ground support, etc) over a dedicated missile type weapon or guided bomb.
There's nothing indicating that the "Cannon Fighter" couldn't carry standard missiles and bombs so the obsession with which system is 'better' is a bit disingenuous at best. It 'might' have been applicable in the original thread but here the main question is does carrying ANY type of gun relate to future fighter aircraft. I'd say yes they will and the Cannon Fighter particularly is an interesting concept.
LowObservable did in fact put it into context:
[URL unfurl="true"]https://www.secretprojects.co.uk/threads/the-future-of-aircraft-mounted-guns.31221/#post-342670[/URL]
Note warhead size is subjective but the 105mm/90mm RR round and 105mm/155mm artillery warhead mass while about half or less than that of a standard AIM warhead can have the same fragment and penetration effect. They are of course vastly lighter than say an AGM or Guided-Bomb, but they are also vastly cheaper, even assuming "upgrades" such as guidance and propulsion for extended range and can have just as good damage effects. Range IS an issue compared to a missile but not as much as everyone seems to be thinking since "standard" artillery ranges with no augmentation is over 12 miles, (and keep in mind air-launched extends that with any kind of body lift on the shell) over 20 miles with rocket assist and that's far from the 'best' propulsion available. Currently ranges of over 60 to 100 miles are possible with ramjet powered (https://www.thedrive.com/the-war-zone/21531/yes-this-is-a-ramjet-powered-artillery-shell-and-it-could-be-a-game-changer) rounds so even BVR-A2A missions could come within the capability of a "simple' gun system. (And we should keep in mind that "simple" sub-sonic ramjets can reach speeds in excess of Mach-8 so a dual-mode grain solid could 'cruise' at Mach 4 and then 'burst' to Mach 8 for final run-in)
Also as noted "gunship" type aircraft and/or mission become very much more capable when such augmentation is added to 35mm and 105mm projectiles extending ranges to well outside possible MANPAD and even some Anti-Aircraft Artillery ranges with little or no loss of accuracy or response time.
Now as the above article notes you'd essentially be launching 'mini-missiles' on some of the more sophisticated examples, (which some critics pointed out would be a 'better' idea anyway) with a simple and robust "launcher" that gives a more efficient initial speed boost than a simple rocket motor which has a lower detectability than a missile launch.
Combine this with the computerized weapons aiming system (F15-era Integrated Flight and Fire Control, https://www.ausairpower.net/AADR-IFFC-Sept-82.html) mentioned by Kcran567 (https://www.secretprojects.co.uk/threads/the-future-of-aircraft-mounted-guns.31221/page-3#post-342959) and Low Observable (https://www.secretprojects.co.uk/threads/the-future-of-aircraft-mounted-guns.31221/page-3#post-342964) and current data-sharing technology and it has a potential of being quite the potent weapon system. (And defensive as well. Imagine a flight of aircraft detecting one or more BVR missile launches, the Cannon Fighter aims and fires several 'beehive' rounds along the detected approach vectors where the shell internal seeker aligns and then detonates the warhead and each BVR runs into several large clouds of high closing speed flechettes, not to mention the launching aircraft getting some tossed their way too)
On the attack let me first say that long range missiles will still play a significant role but the idea of a 'cannon' armed version of a strike fighter or bomber has merit as well. For example the F-117 could only carry two (2) munitions (LGBs or gravity bombs due to way the weapons bay worked) or around 4,000lbs of striking power. Now imagine a version armed with say a single 105mm Recoilless Rifle type weapon (462lbs, but we'll assume a round 500lbs) with an autoloader, (can't find a weight for such a system but we'll say 200lbs, and add in another 340lbs for structure and ammo storage and feed system for a total of 1,040lbs) and various rounds of ammunition to (@134 rounds at 22lbs each, but we'll double it to 44lbs each to assume range extension and guidance are added so only 67 total rounds on-board) make up the 4,0000lb strike load of the F-117. Effective attack range is around 12 miles or more and the aircraft now has to capability of attacking over 10 different targets, (assuming three {3} rounds per target and keep in mind the F-117's "job" is mostly air defense suppression with some deep strike missions) on a single sortie rather than just two. Does it have the impact of 2,000lbs of an HE guided bomb? No but do you NEED that much impact when you can attack literally 10 times the targets with a single aircraft/sortie? And I'm assuming using the "light-weight" RR rounds instead of the heavier standard artillery rounds which you can do using a liquid/ECT or other firing method, at which point your "load" is of course reduced,(103lbs per 155 round, 19lbs for a 105mm) but all your performance metrics go up as well. (And since you're flying an aircraft with on-board aircraft fuel a liquid firing system may in fact make sense despite the complexity, you also have other options for recoil reduction)
Now how 'stealthy' such a cannon-armed aircraft may or may not be is a question that would need to be answered but the possible benefits are there to do a proper trade-off with. Can it work? Sure there's no question there. Would it be worth pursuing? Maybe, again the trade-offs are there and it really depends on the mission and context if it would be right for any 'general' fighter type or only in a specialized role. The idea for use on a "gunship" class aircraft is most certainly quite interesting and viable, its use in other airframes isn't so straight forward but is certainly plausible and worthy of consideration.
Randy
Edit: Re-read the posted report and it was in fact a late-study which is even more interesting
Looked for either the Texas Instruments 105mm Guided Anti-Tank Projectile on-line and the searches default to either the Javlin ATGM (https://en.wikipedia.org/wiki/FGM-148_Javelin) or the Copperhead CLPG (https://en.wikipedia.org/wiki/M712_Copperhead) which I'm guessing it's a version of the latter. Similarly looking for the General Electric Armament Systems RR just defaults to the standard M40 RR (https://en.wikipedia.org/wiki/M40_recoilless_rifle) so nothing there but the weapon system is still in use and production in other nations so...
And since we're on the subject there's even other options such as a new system based on the M3/M4 (Carl Gustaf, https://en.wikipedia.org/wiki/Carl_Gustaf_recoilless_rifle) which has gotten a guidence system (https://www.popularmechanics.com/military/weapons/a23708392/army-recoilless-rifle-carl-gustav-laser-guided-warheads/) in 84mm. And while expensive in the main guided, extended range artillary is becoming pretty common.
[URL unfurl="true"]https://en.wikipedia.org/wiki/M982_Excalibur[/URL]
[URL unfurl="true"]https://en.wikipedia.org/wiki/M1156_Precision_Guidance_Kit[/URL]
[URL unfurl="true"]https://en.wikipedia.org/wiki/XM395_Precision_Guided_Mortar_Munition[/URL]
