[GGpaX4DumpedTea]

OO will penetrate walls. I would go with #4 buck (.24”) indoors. Way more power than is needed indoors and less wall penetration.

Your point is well taken. However, my choice has been Herter’s Defense Shotshells, 12 ga 2-1/4“ #00 Mini-Buckshot — Mini-buckshot has less felt recoil than full-size buckshot shells. These short shells can also increase your magazine capacity. These shells also have less wall penetration.

[Vaquero]

I have a pack of Aguila short slugs. In my Mossberg and Sears (Winchester) pumps the short shells tend to jam.
There is 2 3/4” low recoil Ammo out there. As I often reload 12 gauge I have to look up some low recoil data. I have seen it out there.