!2, or even a 20 gauge shotgun. And for distances inside the home, even waterfowl loads with large steel shot are good.
It is a common misconception that you can’t miss with a shotgun.
You can.
Anyone who has ever shot trap or skeet knows better.
Even a 12 gauge REM 870 tactical with its shortest legal barrel of 18.5 inches and 00 Buckshot will only spread a pattern more than a foot diameter at about or beyond 40 feet.
And gets much tighter proportionally at closer ranges you would have indoors.
OTOH, a Taurus Judge with a .410 birdshot will have very wide pattern in a relatively short distance.