When I went through basic, some 20 some odd years ago, we actually had a guy in our platoon ask the DI this exact question. His response was as follows: “Here and during any kind of qualifications, every mag and every piece of spent brass had better be accounted for or its your ass.

Once you get downrange, if you have to engage from a guard position inside the wire, every mag better be accounted for or its your ass, but if you’re in the middle of a raging firefight outside the wire, your only focus should be keeping yourself and your squad alive and nobody gives a fuck about that mag.

It’s highly encouraged to try to hang onto it or retrieve it once the fight is over and the area is secured, but nobody is gonna break your balls if it doesn’t happen.

Moral of his explanation was that if you’re in a controlled or semi controlled environment, there is no excuse for why every piece of equipment shouldn’t be accounted for. In a hot uncontrolled combat situation trying to keep track of an $8 magazine isn’t worth getting yourself or a teammate killed over.