M576 40 mm grenade

The M576 is a US Army designation for a type of 40mm grenade cartridge. The M576 is a buckshot loading for the M79 single-shot grenade launcher. It was designed to give the soldier carrying the M79 a powerful cartridge for close-quarters combat such as found in clearing buildings, bunkers, and trenches, as well as thick vegetation.

When 40 mm grenade launchers were first developed, the weapon was to be the primary weapon of the infantryman carrying it. It was quickly found that in most engagements while the grenadier gave the squad a decided force multiplier, they were also decidedly exposed if presented with an enemy within the arming distance of most high explosive rounds. Even rounds with a shorter arming distance presented significant danger to the shooter if used at those ranges. Prior to development of grenade launchers attached to standard infantry rifles, development commenced on non-explosive cartridges to allow those armed with launchers to engage targets at shorter ranges safely.

The M576 contains 20 pellets of #4 buckshot for shotguns. The XM576/XM576E1 was standardized to become the M576. Another test variant, the XM576E2, which had 27 pellets of #4 buckshot without a sabot within the shot cup was deemed to spread too quickly for effective use. Both types had a muzzle velocity of roughly 880 ft/s (268 m/s).

By comparison, the M257 12-gauge shotshell is loaded with 27 pellets of #4-buck traveling at about 1,335 ft/s (407 m/s).

Currently, studies are being performed to study the suitability of the M576 cartridge in the M203. [ [http://www.globalsecurity.org/military/systems/munitions/m576.htm GlobalSecurity.org] ]

Notes