In past years, hunting with one of them -eh- other muzzleloaders, I have used conicals (385 gr. .50 great plains bullet), had one of them punch through the deer and not expand at all.
Later, using an 240 gr. XTP hollowpoint in a .50 sabot, I shot a buck at 30 yards using 85 grains of powder, only to have the bullet expand so fast that it bounced off the ribs, travelled around the rib cage through the shoulder muscles and stopped in the neck. I got that buck, but I sure will never use that type of bullet on game again.
Roundballs only from then on for me.
Steve