yeah we have in our training time standards on clearing, disassembly, reassembly, then functions check. the M4/M16 is easy i didnt touch one from 2004-2011 (2004 i went to basic the first time, didnt make it so they chaptered me out, and last year i was able to go back in the military after doing a bunch of stuff trying to get back in) and in that time i still remembered exactly how to disassemble and reassemble it.
Battle is a pure form of expression. It is heart and discipline, reduced to movement and motion. In battle, the words are swept away, giving way to actions-- mercy, sacrifice, anger, fear. These are pure moments of expression.