Most of these comment have said a lot, but lemme just say, a rifle is not for “long range” while a pistol is “short” like a couple people are trying to say. Even for a shotgun. Anyway, former infantryman here. Get a 12 gauge shotgun. Get slugs, bird shot, and buck shot, you’re going to be fine in 99% of situations.

A rifle is more versatile, but, unless you’re putting the time in, it’s not worth it. However, it’s easier to handle than a pistol. Your rifle, just like your shotgun, can handle indoors just fine.

Handguns are for concealment. They’re much harder on the shooter to use, and require more time to become proficient. Short barrel length means weapon handling is down, accuracy is out the window, but, if you need a gun and you don’t want someone to know you have it, it’s your only option really.

If you're not a gun person don't bother with a rifle or handgun, get a shotgun.

You don't have to worry about over penetration with a shotgun, and it's easier to hit with than a pistol.

If you want to know what a proper rifle is, then that's really a subjective assessment. I would say that a 22lr is ok, unless you need fight people in body armor. But I can see how big burly Muricans want something in 338 lapua or 50 bmg.

Easiest way to put it is this way.

Rifle - Long distance shots. Semiautomatic rifles like AR-15 types put out a lot of bullets with precision and are a good way to protect a perimeter.

Pistol - Medium distance. Kill or wound in situations where you can see the white of their eyes.

Shotgun - Short distance (indoors) and highly versatile. You can even load it with "less lethal" ammo.

Knife/baton - Hand to hand combat.

I am not a hardcore gun aficionado so please, I encourage further feedback.

A rifle is for long range, a pistol for close, and a knife/baton for arms reach. Why you may need all three depends on your situation. If you have a yard, a handgun is going to be difficult to safely use at anywhere beyond 25 meters for most people, so that's where the rifle comes in. If they are at your door or in your house, that's what the pistol/shotgun are for, with a knfie or baton as a backup. You do not want to be shooting a rifle inside your house. The noise will be horrendous, and the bullets will over penetrate through targets and the walls behind them. As far as a proper rifle goes, your best bet is an AR15 for a few reasons. They are cheap, readily available, have a plethora of customization options, and most importantly are generally extremely reliable. Another option worth considering is a pistol caliber carbine. This is a rifle length setup chambered in pistol rounds, which reduces recoil and ammunition cost, and if you can use the same ammunition as your pistol. If done properly, you can even interchange the magazines between pistol and rifle. A baton is fantastic to keep on hand because you are less likely to get a major injury if you mishandle it. Any questions let me know!

Talking "proper" calibers is the equivalent of what Linux distro is best. It comes down to how accurate and quickly can you shoot under pressure. By most standards a .22 is too light a round to stop someone, unless you can precisely hit the head and potentially multiple times. A 9mm is kind of gold standard starting point for self defence. Like someone mentioned, if you aren't a great shot, or feel like under pressure you wouldn't be accurate, grab a shotgun. Just racking one can stop some people from attacking.