I have thought of that myself and wondered... . If that projectile is turned around and loaded with the open end in, would setting off the charge behind it expand the 'skirt' in the barrel as would a Minie ball?

For pig killers, I'd think they'd perform well with the open end forward (no plastic tips installed). The shape looks like it may be great for the (pre M1924) Schoenauer magazine.

Problem for me is, they're brass. Where I live, even a trace of lead is verboten while hunting. They'd have to be certified (and accepted by the legal gods) as 'lead free'.