posted on Mar, 13 2013 @ 12:56 PM
reply to post by Wrabbit2000
the m4 is a shortened version of the m16.
not much difference between military and civilian, other than materials used, like hardened steel, and some other small differences.
the trigger assembly is not the same.
the bolt carrier assembly is beefier.
the bolt itself is a specific kind of steel.
mostly better quality materials, and tighter tolerances on military.
the lower on a civilian ar is not milled out to accept a sear.
and it is illegal to machine that part of the lower, to accept a sear.
the lower "is" the gun.
as far as i know the uppers are the same, and are not regulated at all.
some m4 s have a direct impingement system, instead of gas piston.
i'am no expert but the uppers would probably be a little different for direct impingement.
edit on 13-3-2013 by bjax9er because: (no reason given)