The R Series of combat assault rifles was used reliably following the discontinuation of the M Series in the early 21st century. The R series, produced by civilian manufacturer Stent Security Solutions, was made in many models and variations. The variation most common to Washington, D.C., was the R91 full-auto urban assault rifle. The R91 assault rifle was issued in the United States Armed Forces during the urban pacification operations and combat.
Since the National Guard had been fully deployed around the DC area during the time of the Great War, the R91 is readily available for those willing to search around this area. Although nearly two centuries of scavenging has reduced the numbers of working units, the R91 remains a favorite of slavers, raiders, and mercenaries in the Capital Wasteland.
The hardened assault rifle is an improved fully-automatic magazine loading rifle featured in Fallout Shelter. Dealing a minimum of 8 damage per attack, it has the third highest damage output for a rifle in the game.