in have shot several deer with the sabot pistol hollow points i don't think they expand at all unless they hit bone i think they are a waist of money the bullets aren't traveling fast enough .i get the same results with lead bullets i cast myself complete pass through.what do you think?
I think there are a few million deer that would disagree with that statement. So i think you are either using the wrong bullet, or you are not using enough powder in your rifle.
The Hornady XTP for instance, has probably killed more deer out of inline muzzleloaders since Del Ramsey started manufacturing sabots in the mid to late 80's than any other bullet on the market.
They surely don't need to hit bone to expand, most hollow points will expand when entering tissue or body fluids, it is how they are designed to operate. Mammals are comprised of around 80% water.