The irony is a bit dripping. IIRC, a former employee of H&K was tailed home, while being shot at, by some meth freaks, from a gun show. The guy had just bought a machine gun, and, drove to his place of work, parking lot. He jumped out of the truck, grabbed the machine gun out of the back, and put a warning burst in front of the bad guy. The bad guy committed suicide, forcing him to shoot the guy. The DA filed charges, and, after loosing his job, and a couple hundred thousand dollars, he was acquitted, or found not guilty.
That is the only instance I know of, where a submachine gun was used for ANY defense, or crime.
That said, I can't imagine anything much more effective then a 45 caliber burst from a Mac 10, with a suppressor.
With no recoil to speak of, I would think it would be accurate enough at home defense ranges, though the rather heavy bolt, and heavy trigger aren't exactly target quality.
Problem is, most subs I've played with did NOT like hollow points. Ball only. Wonder how that Federal ammo that starts out as ball, and, spreads out would work in a sub?
I'm NOT sold on a shotgun, simply because of the recoil. Semi auto battle rifles, or, any of the surplus carbine guns with 30-06 type ballistics are proven, and, have 1/4 the recoil of 00 buck, in a light, handy shotgun.