"Silent" small arms ammunition


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Jan 30, 2008
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Greetings all,

I have just finished reading the article "Military Pistols: Requirements and Technologies" in the October issue of Military Technology magazine.

In the article is a section on "silent pistols" (on page 86 of the magazine). Here is mentioned four different types of "silent"ammunition. The Russian 7,62x42mm SP-4 is well known (http://www.quarry.nildram.co.uk/sp-4_topE.jpg - unfired on the left, fired on the right - and http://world.guns.ru/ammo/sp-e.htm#SP-4), as is the American .40 QSPR (http://world.guns.ru/handguns/hg213-e.htm).

Both these designs use a captive piston in the cartridge case, situated between the (necessarily small) propellant charge and the projectile. Upon firing the propellant gas pushes the piston, which pushes the projectile. Once the piston reaches the mouth of the cartridge case it is "captured" by a crimp or ridge in the case, holding back and containing the propellant gasses, preventing them from escaping rapidly. This seriously reduces the noise of firing, reportedly almost to the level of the "click"of the hammer/firing pin striking the primer. According to http://world.guns.ru/handguns/hg213-e.htm: "The sound signature of QSPR round fired from QSPR revolver was about 110 dB, or similar to that of traditionally silenced .22LR"

The article, however, also mentions two other "silent"cartridges, claimed to have been developed by Knight's Armament Company: The "5.56-38 Special" and the "7.62-44 Magnum".

Based on the cartridge designations, I would guess that these two use a sabotted 5,56 projectile in a .357 Magnum case, and a sabotted 7,62mm projectile in a .44 Magnum case respectively, but this is just guesswork.

Any further information on these two Knight's Armament calibers would be greatly appreciated, e.g. test and ballistics data, photos, blueprints, etc.

Regards & all,

Thomas L. Nielsen


Blogger http://defense-and-freedom.blogspot.de/
Oct 18, 2008
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Similar exists for 51 and 60mm mortars and a 30mm underbarrel grenade launcher.

There was supposedly also a silenced shotgun cartridge (in addition to a silent shotgun ammo revolver).


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