Yeah for self defense purposes you want either a .357 mag, .40 cal, .44 mag, or a .45. All have great knockdown/stopping power. The .44 is by far the most powerful of the 4, but you will put a hole in 2 walls behind the guy lol. Personaly I like the .45, it does not look super impressive on the ballistics table, but it has tramendous stopping power. The only problem with these guns are they will easily go through the person (if used for self defense) and you will have to worry about what is behind them, though that is always a consideration no matter what/where you shoot. If you are really worried about home self defense your best firearm of choice is by far the 12 gage shot gun. You DO NOT need to unload buckshot into someone to stop them! A simple #6 low brass field load will do just fine, if it can blow an 6" hole through a 3’4" sheet of plywood at 15 feet, it will easily take down anybody. That and it will not put others in danger by going through several walls like buckshot.