If the cam roller slides forward, it pushes the feed cam to the proper against a return spring. Once the cam roller slides backward, the spring pushes the cam again into the remaining. The feed cam lever is hooked up to your spring-loaded pawl, a curved gripper that rests in https://machguns.com/product/lot-1460-military-armament-corporation-m10a1-smg-silencer-class-iii-nfa/