The .50 Beowulf is a 12mm caliber

rifle cartridge A rifle cartridge is a firearm cartridge primarily designed and intended for use in a rifle/carbine, or machine gun. Types Full-powered A full-powered cartridge is a rifle cartridge used interchangeably between service rifles, sniper rifles ...

developed by Bill Alexander of Alexander Arms for use in an

AR-15 An AR-15-style rifle is any lightweight semi-automatic rifle based on the Colt AR-15 design. The original ArmaLite AR-15 is a scaled-down derivative of Eugene Stoner's ArmaLite AR-10 design. The then Fairchild Engine and Airplane Corporation d ...

rifle.

Design and specifications

The cartridge utilizes a

rebated rim A rim is an external flange that is machined, cast, molded, stamped, or pressed around the bottom of a firearms cartridge. Thus, rimmed cartridges are sometimes called "flanged" cartridges. Almost all cartridges feature an extractor or headspacing ...

, sized to match the rim of the

6.5mm Grendel The 6.5mm Grendel is an intermediate cartridge jointly designed by British-American armorer Bill Alexander, competitive shooter Arne Brennan (of Houston, Texas) and Lapua ballistician Janne Pohjoispää, as a low-recoil, high-precision rifle cart ...

round. The case body is very similar in dimensions to the .500 S&W Magnum

revolver A revolver (also called a wheel gun) is a repeating handgun that has at least one barrel and uses a revolving cylinder containing multiple chambers (each holding a single cartridge) for firing. Because most revolver models hold up to six roun ...

cartridge, being slightly longer and fully tapered for automatic feeding in the weapon. The round is intended to improve

stopping power Stopping power is the ability of a weapon – typically a ranged weapon such as a firearm – to cause a target (human or animal) to be incapacitated or immobilized. Stopping power contrasts with lethality in that it pertains only to a weapon's ...

greatly at short- to medium-range as compared to the standard 5.56×45mm NATO round. One of its advertised uses is at vehicle checkpoints, since the heavy bullet's flight path is not easily deflected by auto glass or standard vehicle body panels.

Design limitations

With normal bullet weights between , overall

cartridge Cartridge may refer to: Objects * Cartridge (firearms), a type of modern ammunition * ROM cartridge, a removable component in an electronic device * Cartridge (respirator), a type of filter used in respirators Other uses * Cartridge (surname), a ...

length shorter than that of an

magazine well, and holding to pressures of 33,000 psi limited by the AR bolt strength system, the .50 Beowulf is best described as a low-velocity, heavy caliber, making its ballistics roughly equivalent to those of early

.45-70 Government The .45-70 rifle cartridge, also known as the .45-70 Government, was developed at the U.S. Army's Springfield Armory for use in the Springfield Model 1873, which is known to collectors as the "Trapdoor Springfield." The new cartridge was a rep ...

rounds rather than the higher pressure rounds tolerated by

lever-action rifle The toggle-link action used in the iconic Winchester Model 1873 rifle, one of the most famous lever-action firearms Lever-action is a type of action for repeating firearms that uses a manually operated cocking handle located around the trigger g ...

s such as the Marlin Model 1895.

Proprietary status

The .50 Beowulf is a

proprietary {{Short pages monitor