7mm rem mag. i have shot from seventy five to almost five hundred yard and it does the same job every time, with a lung and heart shot they run about 75 yards and drop hard, hardly any blood when you hang em and slit the throat. Even for as big of a cartridge, it really leaves a nice clean wound, usually exiting with not much bigger of a hole than the entry. That and it shoots so nice and flat with winchester 145 grain ballistic silvertip shells. I hope to work up my own handload this year, will just have to see if i have the time.