Close Quarters Battle Receiver - Simple English Wikipedia, the free encyclopedia


An M4A1 with close quarters battle receiver

The Close Quarter Battle Receiver (CQBR) is an alternative upper receiver for the M4A1 Carbine. It was developed by the US Navy.

A M4 upper receiver with a shortened barrel of 10.5” inches in length and has two variants, the Mod 0 and Mod 1.