Using a rifle for close quarters home defense probably isn't the best option. Dude could be ducking into random rooms and while you're tunnel-vision hyper-focused and a little jumpy with the adreneline pumping, the blood pounding in your ears, you won't take notice of just how close you are to the walls that surround you. Suddenly you hear something from behind and trying to react to it do a quick 180, but end up getting the barrel stuck on the structure and then you got a knife in the gut; RIP you lost that game of Fortnite. I just think a rifle could end up being too clumsy to be optimally effective, especially if you live in a place with tight halls and narrow doorways. I personally feel that in a civilian CQC situation a decent high-capacity handgun or a short-barreled 6+1 pump-action with a cylinder choke and some 00 buckshot would be the way to go.