in all honesty, a semi-auto shotgun with an extended magazine would be a far more devastating weapon than a machine gun. M16’s shoot varmint hunting rounds (.223). The fact that you can hold the trigger in and it continues to fire rather than having to pull the trigger for each round really doesn’t make the weapon more dangerous IMHO.
I mean, anyone can go out and buy a .50 cal that you could use to shoot down airliners, but a varmint gun that cycles automatically is what we’re worried about. It’s all about the image and the stigma that these weapons carry. Not that YOU didn’t know this, speaking to everyone in general.