What is your designated "shoot the perp" gun?

All of 'em.

hahahaha same here.

My "when things go bump in the night" go-to gun is a Winchester 1300 Defender, 12 gauge pump action shotgun loaded with low-recoil Federal LE Flitecontrol 00 buckshot.

I don't believe I'd be posting in public a statement basically saying......... "This here is the gun I been plannin' on shootin' me some people with"

I do like "all of them" however

As I will be responsible for plugging and patching any damaged materials, I generally utilize an AR-15, as it won't make quite the mess of a 12 ga.
If you don't have something set aside for it, waiting till you hear shots in the night is a bad time to decide. BTDT.

The firearm I would consider legitimate for stopping a violent criminal from feloniously injuring my person, should the need to protect myself arise, would be one that uses a metal projectile.