Gww, why do you miss more often with a hot load? There's no recoil until the projectile leaves the barrel, so you may be flinching in expectation of the recoil.
My choice of a weapon to keep beside my bed is my Glock .40 caliber with a Crimson Trace laser sight and, because an intruder would be in my home, I'd put the red dot somewhere in the top part of the head. The guy in the church shooting may have been wearing body armor, so a head shot would have ended the discussion right there.
Ace, I assume when you refer to a semiautomatic, you're talking about a long gun. A long gun takes longer to move around into a new firing position, so a handgun, revolver or semiautomatic, is at an advantage at close range. But my number one choice for a defensive weapon would be a pump-action 12-gauge shotgun loaded with number 4 buckshot and an extended magazine. After going through an FBI short course many years ago, I'm convinced a perpetrator would have no place to hide.