Aartsengel Wapenfabriek Machine Karbijn 31

The MKb. 31 is a gas operated, flapper locked, striker fired infantry rifle, developed in the late 40s by Aartsengel Wapen en Munitie Fabriek. It was a wholly private venture, and meant primarily to replace the myriad of personal weapons found in the hands of ArchSec (then Aartsengel Private Enforcment) personnel at the time. There was also hope that it would become the standard infantry arm of the Western World, analogous to the yet unrevealed Kalashnikov rifle.

Work on the MKb. 31, then MKb. 46, began in late 1945 and was based initially in captured StG 44 rifles. It was decided early on, however, that the StGs tilting block action would be unsuitable for the MKb. project, due largely to it's need for a heavy machined receiver. Instead, the decision was made to use a flapper locking system. This was seen as beneficial, as the flappers could lock into recesses machined directly into the barrel itself, rather than the receiver as necessitated by the tilting block. It was also deemed necessary to replace the original long stroke gas operation with a G43 derived short stroke piston, due largely to the latter's smoother operation and reduced recoil.