You should be allowed to defend yourself in your own home with whatever you choose. However, with that being said, you need to think seriously about what weapon you will use when that day comes. While the AK is an ultra reliable weapon, personally I would go with an M4 using FRANGIBLE ammo so as not to punch through walls and hit other people. My choice for an M4 is basically because that is what I have used for years so my muscle memory would be good under a second of high stress. There is also a huge aftermarket for them, they can be configured in any style you prefer, they are accurate, and they are highly dependable if built properly, kept clean and run with quality ammo.