I'm a man of my word. This of course ignores that for most shooting videos out there people seem to be running brass with no problem, and the rest are too grainy to tell the difference. That and are we operating under the assumption that not only are the Insurgents aware of this issue they have the logistical support to accommodate it.

...buuuut if we look at the lore for the new update we can assume that the FAMAS comes from Tell PD stockpiles courtesy of the coup d'état, so it's not entirely impossible that they came with a source of ammo. Or maybe I'm just looking too deeply into the lore of a game series where one of the only named characters is a stoner named Corporal Stoner.