View Full Version : AAI Corp "silent shot shell" ammunition
June 9, 2000, 02:33 PM
This ammunition was produced by AAI for the US Army during the Vietnam War. One use was in a specially modified S7W .44 Magnum revolver used by "tunnel rats"using a .50 caliber version. I would like to find out more about how the cartridge was constructed and how it functioned.
June 9, 2000, 07:31 PM
This type of 'silent' cartridge typically uses either a two piece case, with the case head screwing into the case body, or a bottlenecked case. Inside the case are the projectile(s), a piston, powder, and primer. When the primer and powder are ignited, the piston is driven forward to expell the projectile. However, the case body has an internal shelf/stop which prevents the piston from exiting the case; this effectively seals off any escape of the propellent gases. With the gases trapped in the case and a subsonic projectile, no suppressor is needed.
The Soviets have designed several piston cartridges for use with fixed breech _and_ semi-automatic pistols. They even have a grenade launcher which uses a piston cartridge to propel the grenade.
June 10, 2000, 06:59 AM
Thomas Swearengen excellent reference book The World's Fighting Shotguns has a four page section on the silent shotgun shell. There are also some photos, including cutaway models, and drawings of the shells.
A short synopysis;
It was designed by Robert Schnepfe in 1967 for a U.S.Navy contract for a low-signture munition that could be fired and ejected from standard military 12 gauge shotguns. The munition was required to possess a high hit-and-kill probability at short range in quick-reaction situations to poorly defined targets. When perfected, it was destined for use in jungle operations by navy SEALS and Marine Corps Reconnaissance Teams.
It employed the AAI-patented powder-actuated Telecartridge device conceived originally for use in missiles. It was designed not to rupture during or after the power stroke. It was then adapted to the development of the Silent Shotgun Shell.
By early 1968 samples were being tested. The payload consisted of 12 hardened No. 4 buckshot, arranged in three interlocking rows. Excluding the plastic pusher, the payload weighed slightly more than 0.5 ounce. It was sealed by an aluminuim, cup-shaped closure disc. A sealing compound waterproofed the mouth. It was 2.5 inches long unfired. Fired, the expanded Telecatridge cup protruded from the mouth of the case approximately .32 inch or about the same as the fold crimp on a standard shell.
The prototype rounds had a muzzle velocity of 550 fps, however testing revealed excessive shot dispersion and some failures at this velocity. A reduction to 450 fps solved all of these problems.
The round was said to be quieter in functioning than the mechanical, repicrocating noises of the weapon that fired it. Its sound signature was considerably lower than that of the best firearms suppressors of the day.
It was never manufactured beyond the original prototype test lot though, for reasons of priorities and economics.
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