I have used the Power Belt Aerotip, 270 gr. in a 50cal. ML. I too have had what I call un-desired bullet performance , but only on realyy close shots ... say 50 yards are less. Very seldom do I get pass throughs, which I prefer if for no other reason to know the penetration was 100%, and of course the blood trailing is usually easier on full poass throughs. The load I use does group great and I have taken several decent deer to to 125 yards or so. I have failed to recover one, and to this day am conviunced I missed. But I am not 100 oercent sure. My doogs never found a blood trail and that made me feel pretty certain it was a miss. I hope so. I plan to use up the supply of these I have left and then try something else.