OK That makes sense except the bolt slamming shut is not quiet.
not quiet? If noise is the problem, with an M4 format, one simply holds back the charging handle and let the forward assist do the work. With the older SP-1, M-16, Armalite system, no forward assist, easing the bolt carrier forward was a little trickier but you just stick your finger in it to slow it down. But waddling out of the water isn’t a quiet thing anyway. That first shot will let the whole neighborhood know you’re there.