RE: Lehman Great Plains Rifle.
TDH
What twist does your rifle have? I would guess a 1:48 but never take anything for granted. You may be able to with that rifle and twist but the only way to tell for sure is to shoot it and see what happens at different yardages? Some people can and others can't in the same make of rifle. Normally a 1:48 is great for conicals and okay for round balls but not always great for sabots who like a faster twist like a 1:24 or 1:32.
Eric