IMO, a break action shotgun, even a single barrel, could be an ideal gun for some people, and effective for anyone. An online guy who highly impressed me had set up his nonshooting GF with a smaller gauge single barrel break action shotgun for when he was away, fitted it with a simple side saddle and suitable shells. It's all very well to say she would have been better off with a 12 gauge pump or semiauto, but once you've fired a 12 or any gun in a confined space you're going to know it's not for everyone, 'specially not an unpracticed user. They had everything set up so the master bedroom was her safe room and she could bar the door, shelter behind a piece of heavy furniture, put on the ear pro muffs that were there along with the gun, not forgetting a dedicated cell phone, and wait to either shoot or for the cops to show up. Whole thing was as foolproof as you could get, there were no room-to-room fantasies she wasn't capable of, no huge disorienting pressure waves if she had to shoot, just an effective setup that SHE was comfortable with.