Use birdshot for birds, clays, or steel targets.
Ballistic tests have shown us for decades that bird shot leaves gruesome but very shallow wounds. At any distance it's nothing like a slug. Watch ballistic gel being shot by a 12ga slug. The damage is ridiculous.
Far too often people worry more too much about overpenetration and not enough about stopping the threat.
Use buckshot. 00 preferred.
If it's effective for stopping bad guys its going to penetrate drywall.
00 buckshot might be considered bird shot if you hunt ostrich.
