A lot of email inquiries come in about choice of firearms for home defense. There are a lot of choices out there and a lot of things to consider. If I am to respond honestly, I will tell you that anytime anyone answers this question, they are merely giving their opinion. My answer here is only my opinion as well, so take it for what it is.
The answer is – whatever you are comfortable with.
If I try to give a blanket answer, it would be out of thinking my views are all that matters. An example. My Wife is a tiny person. If I left her with the only option of using my rifle (a Marlin 1895 lever-action 45-70 Govt), using the idea that anything you shoot with it is likely to just fall down and die, but ignoring her tiny stature, she would get knocked down the moment she pulls the trigger…not good.
So, the gun you will defend yourself with has to be, in my opinion, the one you shoot the best.
I love the idea of a shotgun for home defense, but they are not right for everyone. I have a love of the old Coach Guns, the double barrel side-by-side shotguns. If I ever find the right one, I guarantee it will be the external hammers version. With the internal hammers, if you keep it loaded, it is cocked. At least with the external hammers, you have that added safety.
AR-15 style rifles need to be considered as well. They don’t have the recoil issue, and with the right magazine, you would be able to handle the situation if you find your home invaded by a group, provided you don’t live in a State that doesn’t trust you with high capacity. If you like the AR style, they should be on your list to be considered for home defense.
If you want to consider a handgun instead of a long-gun, you will still need to go through the debate of stopping power vs. capacity. And which you are a better shot with. Personally, I love my S&W 686 SSR 357 magnum revolver. Stopping power it has, high capacity, not so much. And there is also the issue of over-penetration. The 357 will punch right through sheetrock and barely notice. I have a 9mm semi-auto (Walther Creed), lower stopping power but it holds 16 plus one in the chamber. And the deal is sealed by the fact that I am a much better shot with the Walther. So, in the interest of safety, I would grab the semi-auto if the need arises. I hope it never does.
And a final word on stopping power, you are not going to war. A person who has made the series of bad choices that it takes to reach a point of home invasion is certainly not a military-grade superman. I assure you, a single shot from a 9mm is enough to make most people stop doing whatever it was that made you shoot them in the first place.
So, there is my opinion. I know this does not narrow down the choices much, but go into a gun purchase with these ideas, as well as knowing that many gun ranges offer gun rentals, where you can try out a gun and see if it works for you. And if you are brand new to guns, most of them offer gun safety training as well as firearms training.
Ask questions, study, train, and go with your personal preference.