Dover Devil MG Project

Hummer

Hummer

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I noticed there was no picture of the Dover Devil. I was a member of the Special Projects Group in the second development phase and thought I would give the world a picture of it. Picture is me demonstrating it at Ft. Benning, Ga 1980. This would have been ser no DD2, 3, 4 or 5. There was a 20MM conversion of it in the works that had been test fired coming right behind it. It had a sight system that calculated range and flight ballistics to 2000 meters in 500 meter increments. It was estimated that the concept as pictured could have been manufactured for $2500.00 each and at the time a M2HB was $10,060.00 each. The receiver was going to be investment cast while the first five were weldments. In 1982 I learned 50 were slated to be built and were going to be subjected to Technical
Feasibility testing at Aberdeen Proving Ground in 1984 or 85 and I was slated to be the Test Director as I was the only one there that had ever seen one. Somehow the funding got canceled to build them and I never found out why.

It uploaded two belts of ammo at same time and there was a shifter than allowed user to alternate between left drum feed and right drum feed. The idea was ball and tracer on one drum and DU penetrators on other for hardened vehicles. The 20MM concept was going to be for BMPs.

Also Russian 12.7MM caches overrun could be utilized by changing the feed drum as a unit and bolt head and be able to fire 12.7MM within maybe 90 seconds.

Click on the below picture for a clearer image.

On another thread I read the system was "not successful" and I do not agree with that statement in that we had probably run 30,000 rounds on them.

UPDATE: I finally found my other pictures of them and they are on a reply below.


5ojRqC9.jpg
 
What an oppurtunity wasted. only have heard claims of the Singaporese adapting some of the mechanism. The simplicity and low weight would have been a great evolutionary base for what became the 'out battery" OCSW.

Thank you for posting the pic. DD pics are rare.

..wasn't aware of the 20mm version or the 12.7mm WP. 12.7mm WP rds are pretty something and plentiful. Imagine 14.5mm and maybe even 23mm WP could have been an adaptations..
 
Somewhere I have pics of the sub assemblies laid out and a pic of the 20MM version. As a temporary fixture we had a Vulcan barrel on it.

What I don't understand is how the copy was made as the only drawings were in our office unless one was loaned out and somebody photographed everything and reverse engineered it.

http://www.bevfitchett.com/modern-firearm-silencers/images/3238_149_115-dover-devil-machine-gun.jpg Here is another picture of it. Don't know where their information came from but it is not being fired by a Marine Expert, the guy was a 2 Star General. He is firing at a steel plate on a frame I welded together at about 400 yards. How do I know this? I took the picture. I should have a big copy of it around here as well. If I find it I will post it in better quality.
The General was so impressed he wanted it displayed at the Marine Corps General Officer Symposium the next day and I was the only one left as the others had gone back to Jersey and there was no cell phones in those days so no way to get hold of them and turn them around. I called in and the project manager Chuck Rhodes told me to take care of it and I did. 63 General Officers and me were there.
 
The CIS 50 isn't a copy of the Dover Devil but a similar weapon using the same kind of principles (gas pistons, rotary bolt, dual feed, etc). Inspired is probably the better word and something the Singaporeans frequently do with differing levels of access to the system acting as source of inspiration (don't get BAES started on the Singo lightweight 155mm gun and the M777 technology package they provided). Here is an old Janes article about the CIS 50 that details a range of differences between it and the DD.

PS Great info and imagery Hummer.
 

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Hummer said:
Also Russian 12.7MM caches overrun could be utilized by changing the feed drum as a unit and bolt head and be able to fire 12.7MM within maybe 90 seconds.
Click to expand...

Thanks for that, interesting. But you forgot to mention you would need to change the barrel as well - the 12.7mm Russian round (12.7x108) was both longer and wider than the .50 (12.7x99) and would not have been able to fit into the .50's chamber.

Pic from the Ammo Photo Gallery on my website:

HMG1.jpg
 
Right on. Actually the 60 cal round was desired but there wasn't enough of it left in inventory to get a safety statement. If memory serves me correctly we had to fire DD1 5000 rounds remotely before it could be man fired.
It was all done at a range of maybe five feet into a water trap. Conversion kits could have been made for about anything with a push forward link system. We did all initial firing with one lot of 50 cal with bad links that had a CONUS only issue restriction. The links were improperly heat treated but the ammo was good so we just burned up thousands and thousands of rounds and about every link was deformed on feeding which the guns did not mind but the links sure became useless on firing.

We had already fired it a couple hundred rounds and an inventation was sent out to all the machine shop personnnel who fabricated the pieces to attend the First Shot ceremony. They were expecting a single shot to mark the event and we gave them a burst. We gave them all an empty case as a momento.

At the Armed Forces Day open house I volunteered to come in and man the display. It was a 37 mile drive for me but I loved what I was doing. I talked to the project manager and told him I had a idea to get the kids interest which was to give them a empty 7.62 case for stopping by the table and he agreed so I went up and got a couple wire bound crates of empty brass and handed a piece to everyone and that really made a hit with all the kids. Considering New Jersey was and still is a very anti gun state I figure I peaked the interest of thousands of kids. Kids being kids wanted more than one and they would keep getting back in line and coming back through. I knew what was going on but I had plenty to give away. Right at the end this one kid comes back and says his Dad would like to have some to reload and wanted to pay me for like 100 cases and I handed him half a crate which would have been a 50 cal can full and told him to have fun with it. Must have been near on 600 cases.

I figure that made for lots of quality time together for that father/son relationship prepping and reloading it all.


We found out quickly the ejection angle was about 5:00 o'clock and the force was so violent that the empty cases struck the 2" thick safety screen which was a Lexan like material with such force that it indented and scarred the surface so a deflector had to be quickly designed to bring the ejection around towards 1 to 2:00 o'clock.

These questions are making me want to go digging for the rest of my pictures and is bringing back lots of great memories for me.
 
Pictures would be appreciated and great for the forum and discussion. :)
 
Hummer said:
Right on. Actually the 60 cal round was desired but there wasn't enough of it left in inventory to get a safety statement.
Click to expand...

That .60 cal was a monster round, originally made in WW2 for an anti-tank rifle. Some early prototypes of what became the M39 and M61 Vulcan aircraft cannon were made in .60 cal, but in the end they decided to neck up the case to 20mm. The pic below shows the .60 cal (15.2 x 114) together with the three other cartridges made from it (the 12.7mm was experimental), with the current US 20mm Vulcan being the 20 x 102. Note that the .60 is even bigger than the Russian 14.5mm KPV round in the second group, and that's twice as powerful as the .50 BMG.

MCRel2.jpg


The 14.5mm is shown with two other cartridges made from it. The 23 x 115 is for aircraft cannon, but the 15.5 x 106 might be of interest to you: it was the final version of the round developed for the experimental Belgian FN BRG of the 1980s which was intended to counter the 14.5mm, but no-one bought it. I understand that at that time, the conventional forces agreement between NATO and the Warsaw Pact limited the number of light armoured vehicles armed with guns of 20+mm calibre, but those with HMGs escaped.

Pics from my web article on Military Cartridge Relationships: http://www.quarry.nildram.co.uk/MilRel.htm
 
I know the Navy Seals were playing with 50/14.5 back around 1990 and were looking for PTRD actions to build them on but haven't heard anything about them since.
 
Hummer said:
I know the Navy Seals were playing with 50/14.5 back around 1990 and were looking for PTRD actions to build them on but haven't heard anything about them since.
Click to expand...

PTRD instead of KPV - so they wanted a rifle rather than an MG?
 
Makes sense -- SEALS have had an interest in long-range anti-material sniping for quite a while (at least since the Panama fiasco.)
 
What was the performance of the 12.7x114 like? It's a lot of case for a relatively small projectile.
 
Kadija_Man said:
What was the performance of the 12.7x114 like? It's a lot of case for a relatively small projectile.
Click to expand...

42.8 g at 1200 m/s, or 32.4 g at 1340 m/s.

This round was developed for the USAAF in WW2, who wanted to improve the hit probability in air-to-air firing by minimising the bullet flight time, so wanted the highest possible muzzle velocity. It did not proceed.
 
some information on dover devil hmg
 

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other photographs and the patent
 

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For the version in 20x102 , it's for vehicles or it's an attempt (rare) to replace the 12.7x99 ?
There is much more recoil .
 
I finally ran across my other pictures of the Dover Devil Double click on the pics as they come up to see them more clearly. Sorry for long delay in finding these but just ran across them on a back up thumb drive.

EMMH6yV.png



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JNAm7pz.png
 
Hummer said:
I noticed there was no picture of the Dover Devil. I was a member of the Special Projects Group in the second development phase and thought I would give the world a picture of it. Picture is me demonstrating it at Ft. Benning, Ga 1980. This would have been ser no DD2, 3, 4 or 5. There was a 20MM conversion of it in the works that had been test fired coming right behind it. It had a sight system that calculated range and flight ballistics to 2000 meters in 500 meter increments. It was estimated that the concept as pictured could have been manufactured for $2500.00 each and at the time a M2HB was $10,060.00 each. The receiver was going to be investment cast while the first five were weldments. In 1982 I learned 50 were slated to be built and were going to be subjected to Technical
Feasibility testing at Aberdeen Proving Ground in 1984 or 85 and I was slated to be the Test Director as I was the only one there that had ever seen one. Somehow the funding got canceled to build them and I never found out why.

It uploaded two belts of ammo at same time and there was a shifter than allowed user to alternate between left drum feed and right drum feed. The idea was ball and tracer on one drum and DU penetrators on other for hardened vehicles. The 20MM concept was going to be for BMPs.

Also Russian 12.7MM caches overrun could be utilized by changing the feed drum as a unit and bolt head and be able to fire 12.7MM within maybe 90 seconds.

Click on the below picture for a clearer image.

On another thread I read the system was "not successful" and I do not agree with that statement in that we had probably run 30,000 rounds on them.

UPDATE: I finally found my other pictures of them and they are on a reply below.


5ojRqC9.jpg
Click to expand...
My father worked on developing this gun at Picatinny Arsenal. He was an engineer in the project.
 
Yes, that was the easiest route to get them made up.
Tony Williams said:
Hummer said:
I know the Navy Seals were playing with 50/14.5 back around 1990 and were looking for PTRD actions to build them on but haven't heard anything about them since.
Click to expand...

PTRD instead of KPV - so they wanted a rifle rather than an MG?
Click to expand...
t
 
The main patent
https://worldwide.espacenet.com/pat...725791/publication/US4311082A?q=pn=US4311082A

Applicants​

US ARMY

Inventors​

CURTIS JOHNSON; PHILIP BAKER

Published as​

US4311082A

There is at least one secondary patent, related to the feeding mechanism.
https://worldwide.espacenet.com/pat...208524/publication/US4587879A?q=pn=US4587879A


Unsurprisingly the main patent sites the patent for the XM235 SAW contender and XM248 (Curtis Johnson is listed as the first inventor there too). XM235/XM248 used a two-tube frame and sprocket feeding.
https://worldwide.espacenet.com/pat...443293/publication/US3999461A?q=pn=US3999461A
 

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Rickshaw said:
What was the performance of the 12.7x114 like? It's a lot of case for a relatively small projectile.
Click to expand...
Based on the Anzio 20/.50, which is a 20x102mm case necked down to .50cal, muzzle velocity of about 3600fps and a supersonic range of about 2500y. Using the 900gr A-max bullets. Think it'd be up to about 3800fps with a lighter 692-750gr bullet.
 
Are the pics loading for you folks. I can't get them to open???????????

I found out Curt Johnson died a few months back. He wanted to be cremated and ashes buried in a ammo can and he was.
 
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