I cannot see what it won't tumble.

V-nice target from your 16 bore rifle. Good ballistics, too.

Mike I would not worry about over-stressing the tubes with black powder loads and tight wads.

One thing about tight wads, though, is the possibility of them being pushed back up the tube by compressed air between then and the nipples if the hammers are still down on the spent caps, or between the overshot and over powder or fiber wads.

Many of the guys I shoot with, cut a small cut or knotch in the wad before seating it, which lets the air past and does not seem to effect patterns at all. They use a pocket knife, patch knife off the strap of the shooting bag, or simply their thumb nail.