| 摘要 |
A modular automatic or semiautomatic rifle. The rifle has a lower receiver assembly having a fire control assembly for firing the rifle. An upper receiver assembly is provided with a frame and a bolt carrier assembly configured for firing bullets of a predetermined caliber. The lower receiver has a mating interface configured for operably joining the lower receiver assembly to the upper receiver assembly, and for operably joining the lower receiver assembly to another upper receiver assembly different from the upper receiver assembly configured for firing bullets of the predetermined caliber. The other upper receiver assembly has a different frame and different bolt carrier assembly configured for firing bullets of a different predetermined caliber. |
