Rem, i have a 300 H&H mag that i shoot 165 gr. STBT out of. i found that bullet seems to work well out of that gun. one thing you have to remember is that with the heavier bullets moving at faster speeds there is a chance that the bullet can shoot straight through. a cousin had problems with his 7mm mag shooting 180's that went straight through deer and loosing them. no blood trail because the bullet didnt open up. maybe he just wasnt hitting them in the right spot. in my opinion, try the 165s and see how they perform. if you reload try not loading them too fast.