Just for a thought...
I take a rifle, say an AR-15 off a dead guard, because I want to arm myself with a firearm instead of just a knife. It happens to not have any sight on it. WTF knows why, broke off when the guard fell on it, expert trick shooter, WTF CARES.
It is a TV show. Check brain at kitchen counter because the only time you need it is when you are hungry and looking for snacks.
I'm happy when I see shell casings being ejected from guns for realism... Opposed to whole cartridges in flight, AR's w/o buffer tubes, reams of ammo w/o primers, reloading after 4x ammo capacity if at all, car doors and such being bullet barriers.
Watching TV Show Checklist:
1. Guns involved? Check!
2. Shoot stuff and it dies or goes boom? Check!
You notice that plot and realism are not in that checklist...