That's precisely what I was suggesting. While I hadn't anticipated the gas blowing the lead out through the jacket, which I suppose it's possible, I think that would be very unlikely. The main concern as I see it could be accuracy. Modifying the projectile could impart an imbalance to it, producing nothing but "flyers"?
If I had an old sewer pipe Mosin, I'd be doing some experimenting with the ball ammo rather than trying to locate hunting sp ammo.
I suppose my question was; should a game warden come across someone with downed Moose and Mosin in hand, if asked to show the ammo used, would modified ball ammo (if it even works), be legal in the eyes of the game warden, or is he going to be taking a position that it's ball ammo (prohibited for hunting with.)?