Alexander Arms were the developer of .50 Beowulf. It is a rifle cartridge use in a modified AR-15 rifle. The cartridge utilizes a rebated rim, sized to match the rim of the 7.62x39mm and 6.5 mm Grendel rounds. It is very similar in dimensions to the .500 S&W Magnum revolver cartridge.

According to the manufacturer it was descended from the .50 Action Express, a cartridge originally developed for the Israel Military Industries Desert Eagle pistol, with significant modification to improve functionality and safety in the AR-15 platform.

The image on the left is a comparison between 5.56mm (standard bullet for M4) and the Beowulf’s .50 calibre round.

The round is intended to greatly improve stopping power at short-to-medium range as compared to the standard 5.56mm. 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.

See .50 Beowulf in Action, watch the video below.