I have shot a 243 all my life. I have killed about 30 deer and lost one. The lost one was due to my error and shot placement. I shot a buck head-on at 90 yds. I think that I hit just off center and broke his shoulder and never entered the chest cavity. About 90% have been one shot kills. I love my Browning LA 243 for running deer out to 125 yds, never have to lead them(I've shot 4 running). I would defininitely use a partition bullet and not Winchesters. Remington Core-Locts work in 100 gr. have made big exit holes for me. Just place the shot well behind the shoulder. As far as range, I am pretty good with accuracy and I have shot two deer over 300(one at 325 and one at 450, way to far). I would keep my shots under 300 and place well and you will be fine. Good luck.