^ Then buy a semi-auto 12 Ga shotgun.
You can buy or have a friend reload, light target loads that don't hurt your shoulder.
It's hands down, the best home defense weapon there is. It's better than a pump shotgun for the following reason: If you shoot at an intruder, he returns fire and hits your arm, you can no longer operate a pump-action shotgun because it takes 2 good arms to operate the action. A semi-auto, on the other hand, can fire multiple shots with one hand.