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?
Thanks,
John
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?
Thanks,
John
