Quote Originally Posted by RAM Engineer View Post
I think that video is what spurred my question. These Brownells guns seem to use a ball detent lockup. I'm not sure what the original guns used, prior to whichever version had the forward assist integrated.
It looks like there's some sort of roller detent on the back of the charging handle (near the rear of the receiver) that's supposed to keep it from reciprocating. It might just be a shiny wear mark, though.