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U.S. 57mm Recoilles Rifle Experimental Case


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Premium Member
The 57mm Recoilless Rifle was developed near the end of WWII, along with the 75mm Recoilless and the 105mm Recoilless. The 75mm and 105mm versions originally used 75mm Howitzer and 105mm Howitzer projectiles, that had their rotating bands pre-engraved to reduce bore friction and recoil.

The 57mm Recoilless on the other hand, didnt really have a 57mm howitzer to draw from for a projectile design, and the HE projectile from the 57mm antitank gun was much too heavy. To complicate the situation, the 57mm would be shoulder fired, so ammunition weight had to be conserved.

I have posted a photo of a number of 57mm recoilless rounds, along with an experimental case (T109E2) on the far left, and a subcaliber trainer for firing rifle cartridges as training rounds. Addition photos show details of case design. Also, please note that three rounds do not have their projectiles completely seated due to tight unfired case mouths.

Manufacturing changes can be seen in the construction of the cartridge cases, the oldest round on the far right, advancing in date to the left. The shoulder of the first case dated 1945 with a test number starts out as a copper ring. This changed to a steel ring on the next case, and then simply 3 dimples around the neck area. It is interesting to note, that the newest case (dated 1957), the oversized one on the left, regressed back to the next to oldest design of shoulder, but that will be discussed below.

Additional manufacturing changes can be observed by the seams in the case. The experimental oversize (T109E2) and one of the service cases have weld seams up the side. These cases were made by punching flat sheets to make the gas escape holes, then rolling the case into a tube, welding the seam, and then welding on the shoulder/neck. The other cases were made in the conventional way by ironing, and then punching the holes, so the welding process was eliminated. The T109E2 case most likely used the older rolled and welded design, so that ironing dies were not required for the small number of cases reqired for the test. Since the case wasn't ironed, the round ring design shoulder/neck was welded on, instead of using the 3 dimple design.

The T109E2 Case headstamp is shown. F.A.E. 3909 stands for Frankford Arsenal Experimental and the number. Below that Lot #1 1957, and B.M.C. the manufacturer. Most of the other service round steel cases do not have headstamps. The information was inked on, and is now nonexistant.

The difference in design of the rims can be seen, with one of the strangest combinations of characteristics shown on the T109E2 case. It is interesting to note that this oversize case, most likely designed to increase velocity, was experimented on in 1957, whereas some of the projectiles are bearing paint labels from 1974 right at the end of the Vietnam war! The design was evidently abandoned, and the older slower design continued for close to 20 years.

Does anyone else out there have any more information on this subject?




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Very very nice John. Thanks for all the info - sorry I can't add to it.

Interesting article !

Very good article HAZORD and thanks for showing us.
I used to have one of the service rounds (case with no headstamp) and at the time of getting it could not find out anything about it (pre internet days=Dinosaur!) so that has filled in that gap in my knowledge.
thanks for sharing.
here my HEAT shell M307 A1

shell was 1950 dated, by Frankford arsenal, cases, I don't know.....
AEP was Arsenale Esercito Piacenza, but I think was overimpressed....
best regards


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Does anybody have any of the old 105mm Recoiless HEAT Rounds. I have pics of some lives we disposed of. But It would be nice to see one in good condition
very nice to see all these variations. What is the caliber of your subcaliber device for the 57mm? Would also like to know how the firingmechanism of the subcaliber cartridge works.
Will make pictures of mine to compare it.
106MM Recoiless HEAT M344A1

Hello BOMBSaway1980,

Here are a few photographs of my inert 106MM M344A1 Recoiless HEAT round. It's a really interesting round and makes for a great collectible if you're ever able to grab one.

Best regards,



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Hi Hazord,
Thankyou for doing such a informative write up, i have seen some of these rounds and bought one or two over the years and had no idea what the purpose of the copper ring that was on one of them was, now i do. Great item to have in your collection.
Best Weasel.
I was looking for an inert M341 105mm HEAT. I run into a whole lot of 106mm but once and a while I run into the old 105mm from WWII. I've been looking for a good inert example for a restore I'm doing with bits and pieces.


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@fert thought the HEAT was M306A1 - see the pictures.
At least 1961 SMI also made any cases.


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The pictures of Fert's HEAT rounds looks like they are lettered M307A1.

Your HE round has really nice paint! One of the amazing things about this site is that you look all over creation for a round like a 57RR HEAT, and somebody else will have 5 of them, but of course they are half way around the world, and everything into the U.S. is x-rayed these days. I have a HEAT projo and a canister, but I still need the WP.

nice to see your italian round. BPD=Bombrini Parodi Delfino. are the shell BPD marked on the body or paint only???

as you can see HEAT shell was M307 A1 marked

best regards


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the projectiles are also stamped in the steel with 57MM M 306A1 1 BPD 61

do you know the rifle caliber of your subcaliber round?
Is it .30-06?
I think the subcaliber adapter is 30-06, but I need to check. I will shoot some photos of how it comes apart. I can't fire it, because some jackass demilled the barrel near the muzzle with a torch.
I think the subcaliber adapter is 30-06, but I need to check. I will shoot some photos of how it comes apart. I can't fire it, because some jackass demilled the barrel near the muzzle with a torch.

Thanks - would be interesting to know the caliber and see how the thing works - a screw type bolt with inserted firing pin?
A very nice collection! I have picked a few 57mm recoiless rounds over the years, and I have never seen a case with a steel ring for a shoulder. Thanks for the info! I am attaching a couple of pictures you may be interested in. One is a 57mm cannister round, T25E5, and the other is closeup shot of a the standard M306 HE and an early M307 HEAT projectile. Incidently, I use a roll of heavy grey paper to simulate the metal gun powder container. -Rick


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All of them look really nice and new, kind of like they fell out of the truck as it was leaving the arsenal, lol. Hey, I see you have labels on them. How does your labeling system work?

Here some variations and the detail of a casemouth - its the headstamp in the picture - the other one for comparison is the SMI 61 case.


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That case shoulder on your round, is a whole different design. That is very interesting.

I checked the caliber on my subcaliber adapter. It isn't 30-06. It is a bottle-neck round about .260 diameter measured in the rifling grooves at the muzzle.

The design is kind of poor. The round is inserted in the chamber, and then a 1 inch diameter plug is screwed in behind it. The plug has a floating firing pin. There isn't any type of extractor or ejector. The operator would need to run a rod down from the muzzle to knock the empty case out.

I looked through the holes in the case, and could see what looked like a rifle barrel with a hex shape near the chamber end. There were some characters etc. stamped on some of the flats of the hex. One set was 1929 There was also a mounting bracket for what looked like a rear sight or something on the barrel, inside the case.

HAZORD thats the same like the subcaliber device here - thats 6,5 Carcano - you can try such a case in the chamber it should fit. The one here is dated 1928 and there is also the lower part of the rearsight visible through the casing of the 57mmRR.


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