Well most gun shops I know have burglar bars. So I'm not sure if they would get in. But if you wanna play that game. I would only take an AR in the shortest barrel I had, and as many pistols as I could grab. Zombies don't need a caliber with stopping power. they just need to be shot in the head. So I'd probably pack some .22's and since I own a gun shop :) they would all be silenced.