I think a shotgun is a very good idea. Before my TRAGIC boating accident where the boat tipped over..and everything was deep sixed..I had a Saiga 12 semi auto 12 gauge. It did lack that outstanding sound of shotgun being racked. However it threw lots of lead at the zombie that came in the door..very quickly! (Phew..I kept everything in the past tense.)
Flgoldwingguy
Remington Model 870 12 ga pump. This was the shotgun we had in the military and the balance was such that you could fire it one handed like a pistol. Smooth pump action for quick chambering the next round.
And as stated before the noise, flash and sound are such that an intruder will run and not fire back. Plus the fact that a shotgun will be less likely to harm your neighbors property.
I used to love my Springfield 1911-A1 and my Ithaca M&P 12 gauge. I had a very unfortunate boating accident and lost them along with the rest of my guns, and the safe, too.