I guess the 30 round mags are luck of the draw. In '54/'55 during occupation duty in Cold Rear, I'd occasionally "liberate" a 600-round canister of ammo and go to the beach at Inchon with my M2. Spray and pray at seagulls and sea shells and all that juvenile stuff that a 20-year-old will do. Never had any problems with the mags on full auto.
My dad told similar stories about M2s and some sort of prairie dogs or ground squirrels that he shot in the desert, while in the Air Force.
I've shot my Carbine at 12" targets at 350 yards in competition, and while it can be done, the effective range is really closer to 150. I suppose that's why you need an M2 for prairie dogs.