ACP's look pretty strong, too. 9mm ammo is notoriously overpenetrating. Don't even think of using FMJ bullets for 9mm for defense purposes.
Most experts say that a shotgun with birdshot is the best home defense weapon.
The sound of racking the slide of a pump shotgun is unmistakeable and enough to make most sensible burglars flee or soil their pants. You can get these cheaply at Kmart and Target so you can practice at the range. Remember, the larger the shot, the smaller the number.