FMJHP is kind of an oximoron. The open tipped match type bullet can expand but can also pencil thru or fragment. Why they are not the best choice to hunt with in most calibers. A true JHP rifle bullet can certainly expand properly if designed to do so.
"Given adequate penetration, a larger diameter bullet will have an edge in wounding effectiveness. It will damage a blood vessel the smaller projectile barely misses. The larger permanent cavity may lead to faster blood loss. Although such an edge clearly exists, its significance cannot be quantified".