Maybe the op could describe this “home invasion”? Is it one lost drunk stubbling into your house? Six fully armed thugs hell bent on stealing my Jack Russell collection? A thief, maybe a drug addict taking whatever he sees first?
handgun, preferably loaded with rounds using (reliably) frangible bullets. Why?
For one, I live in an apartment, so a rifle or slug gun is out because they look at plaster walls and go “OMG SRSLY?” as they punch right through. Some guy on Youtube did a demo of long gun rounds using multiple simulated walls (drywall/2x4.) Rifle bullets and shotgun slugs punched through all layers of it and went on their merry way.
second, the people who think a 12-gauge is great for home defense have probably never fired one. A short-barreled 12-gauge has brutal recoil and the muzzle blast is a sight to see. And hear, because you won’t be hearing much for a while afterward.
and I hope you’re not seriously asking if a handheld machine pistol (i.e. Uzi) would be appropriate. you’d put more rounds into the ceiling than what you were actually pointing at.
Note that the cops will merrily shoot your dog, regardless of his size, breed, aggressive tendencies or lack thereof. He will later be described on the reports as “pit bull-type” and much will be made of how he aggressively bounded up, tail wagging.
I know right? Who could think that a lightly armed group of civilians and military veterans could stand up to the US military? What do they think, it’s possible to have a decade long war against a military force like that? Absurd!
Running would be the best option if possible. Even if you are armed. As long as it is only property that is at risk. But sometimes running is not possible and most people have family to worry about as well.
I voted handgun. I am very well trained and have used them for years. Right now a rifle or shotgun would be impractical to store and I don’t need that kind of firepower at home. I don’t hunt and there are no rifle ranges anywhere close.
My reasons for choosing a handgun rather than a shotgun:
It’s easier to maneuver in the confines of a home.
It’s easier to shoot (less recoil)
Shooting a handgun indoors is going to do less permanent damage to my hearing than shooting a shotgun indoors
It’s easier for me to securely store (my handgun is in a small safe hidden out of sight under my bed; a shotgun would have to go in a big, obvious gun safe)
The handgun is a more multipurpose weapon for me - I can carry it (with the proper permit) and I can use it for target shooting (I’m not into skeet or trap shooting or hunting - at least not yet).
Contrary to Internet myth, a shotgun DOES have to be aimed when used for home defense, as the pattern spread is minimal at normal room distances. But that long barrel does make it easier to aim accurately, and it has more stopping power than a handgun. Rounds from either a handgun or a shotgun can penetrate walls, so neither weapon has a decisive advantage there.
It’s all a matter of picking what fits your situation best.
“Run” is a fantastic option when it’s available. But sometimes that option’s not there; my bedroom, for instance, is a room I can easily be trapped inside because it has only has one door and the windows are second story over a concrete patio. If criminals bust into my home and trapped me within my bedroom, I might have no choice but to fight, as going out those windows in a hurry is NOT an option. Hence my handgun.
Theoretically, a shotgun. Not sawed-off, because that’s a felony unless you do everything legally. In reality, a pistol as the shotgun is plugged to two rounds for hunting and I’m too lazy to change it every time.
Recoil? 12 gauges have less, especially compared to Mosin-Nagant.
Hearing? I have fired handguns outdoors and shotguns (albeit only birdshot). The former is much louder.
Accuracy? IIRC shotguns are patterned to 40 yards. Even if you have cylinder choke (widest pattern), at indoors distances you still need to aim.
My walls are concrete and the pets are short, so my selection is not limited by penetrability as much.
Dog is little but vicious, but I’d think the type to greet strangers. Hard to round up 4 cats. I don’t have a back door, escape would be jumping out the 2nd story window. Or climbing out the first floor, which is even harder, and would put me right next to the front door.