I killed one elk with my own 257wby mag at 330 yards according to my laser rangefinder.However it was a rag horn bull that was much smaller than some of the mature bulls that I have taken.It did provide a clean kill,but I prefer to use at least .284" bullets for my elk hunting.I only used the 257wby because I took a fall with my 300wby and was not confident that the scope was still on,because I did not have the chance to shoot it before the morning hunt.