12ga is ok depending on the load, # 7 shot isnt so ruff even with a pistol grip, and I prefer a pistolgrip in close confines, but Holy Jesus 3" 00 buck shells will rock yer world in that configuration L0L
Im new to shotguns and the biggest thing I have learned is know your loads.
Another little tip is that you can't hit jack when you shoot shot with a slug barrel.
I have no idea why that is.