US Patent 10557674 Buffer assembly for firearms

A buffer assembly for a firearm with a frame containing a bolt that moves during a firing cycle, the assembly having a case containing a movable piston, a piston spring for biasing the piston forwardly, a spring flange engaged with the piston spring, an end cap for closing the case, one or more resilient washers between the spring flange and the end cap, and a buffer spring in the piston spring that is shorter than the piston spring, so that during a firing cycle, the bolt engage a contact end of the piston to move the piston rearwardly the piston spring to decelerate the bolt until the piston engages the buffer spring to further decelerate the bolt, the resilient washers compressing to contribute to the deceleration.