Vasquez fires Smart Gun

Pvt. Vasquez firing M250 rounds from her M56 Smartgun.

The 10×28mm Caseless round, designated the M250 round in United States Colonial Marine Corps service, is an American-made caseless rifle cartridge notable for being the primary ammunition used by the M56 Smartgun and its variants, as well as the M30 Autocannon used by the UA 571-C Automated Sentry Gun.[1][2]


The round consists of a 230 grain (14.9 gram) projectile encased in a rectangular block of Nitramine 50 propellant.[2] It offers increased power over the M309 10×24mm Caseless round used by the M41A Pulse Rifle, and also incorporates a selectable fuse setting — a switch on the weapon is used to switch between ammunition fusing modes, and the setting is applied to each round electronically as it is loaded into the chamber.[2] The Super setting is optimized for use against soft targets, detonating on impact, while the Delay setting will allow the round to penetrate armor before exploding within.[2] When used in Smartguns or sentry guns, 10×28mm Caseless rounds are stored on a roll of continuous plastic non-disintegrating link belt in an ammunition drum, which can be reloaded in the field.[2]

The 10×28mm cartridge can also be used in the M42A Scope Rifle without the need for modification, although it offers inferior range and accuracy when compared to the rifle's bespoke match-standard ammunition types.[3]

List of 10×28mm Caseless Firearms[]


See Also[]