There are many opinions out there regarding what load to use in your shotgun for home defense. Or even whether you should use a shotgun to begin with. One thing to consider, that is not as well mentioned, is the unwieldiness of a shotgun indoors. It’s obviously not as easy to fit in a nightstand as a pistol. Though your situation will dictate what you choose.
With that being said, at outdoorlife.com they’re using a formula of “Energy =.5 x Mass x Velocity ^ 2,” to make comparisons of terminal energies between different caliber firearms. Your oo buckshot fairs very well.
12-gauge, 9 pellets 00 buckshot (1.107 ozs.) – 1547 ft./lbs.