?? Where do you get that it's going to weigh 50 lbs? This 90-round .223 drum mag weighs under 4 lbs loaded.
I can’t see or understand how or why he would fire the shotgun, discard it, then switch between the rifle and the pistol. The recoil from one-armed shooting would be enough to break someone’s wrist.
Recoil from which? The AR-15 has minimal recoil. The shotgun has more recoil, but a physically-fit man can shoot one one-handed without pain.
I’ve fired an AK-47 with a 100 rd drum mag, and it clocked in easily over 40 lb. Then again, that’s a much larger round than the .223 and the drum itself was made with stamped steel as opposed to aluminum.
You ever fired a 12 ga. shotgun with a pistol grip with one hand? I have. I left the range with an imprint of the heat shield on my forehead, a broken nose, and a sprained wrist. That was after firing just one sabot shell. I didn’t drop the shotgun, so it might be possible, but it’s far from practical.
Again, going back to practicality. Regardless of weight, which I admit I may have overestimated, it cannot be practical to commit this sort of atrocity with the armament as described by the MSM.