i would think a heavier slower bullet would expand better like the 300 gr. xtp-s. i would look at your charge too.maybe too hot? how much powder are you using? i remember the days of using 100 grains. an old timer told me to drop down to 70 for starters and my groups did so much better. i wonder if you can buy ballistics gel. it would be neet to test your personal loads for expansion at different ranges. i have seen many critters hit with a well placed shot and not bleed. they never went far but there aint nothing like a good blood trail.