FWIW:
I've read much about shotgun loads, overpenetration, and dissipation. Finally dragged out some plywood and evaluated it for myself. (Ok, this is hardly scientific.)
Propped up some 3/4" plywood in the back yard and fired #8 shot at it using a 14" barrel (Mossberg 590 AOW) from 1 to 10 yards. Shot size was chosen for presumably rapid energy loss, in consideration of short-range defensive use (i.e.: home defense, with a particular concern about over-penetration).
Shot spread was roughly 1" for each yard of distance.
From 1 to 4 yards, a nice big hole was blown clean through the 3/4" plywood.
At 5 yards, the wad got stuck in the plywood.
At 6 yards, the wad bounced off the plywood, and the shot penetrated 1/8"-1/4".
I've read much about shotgun loads, overpenetration, and dissipation. Finally dragged out some plywood and evaluated it for myself. (Ok, this is hardly scientific.)
Propped up some 3/4" plywood in the back yard and fired #8 shot at it using a 14" barrel (Mossberg 590 AOW) from 1 to 10 yards. Shot size was chosen for presumably rapid energy loss, in consideration of short-range defensive use (i.e.: home defense, with a particular concern about over-penetration).
Shot spread was roughly 1" for each yard of distance.
From 1 to 4 yards, a nice big hole was blown clean through the 3/4" plywood.
At 5 yards, the wad got stuck in the plywood.
At 6 yards, the wad bounced off the plywood, and the shot penetrated 1/8"-1/4".