Lyman Great Plains Hunter 50 Caliber Flintlock Muzzleloader Rifle. This is a special version of our Great Plains rifle with the hunter in mind. Called the "Great Plains Hunter", this new model features a fast, 1 in 32" shallow groove rifled barrel. It's ideal for shooting the many types of modern projectiles available to today's black powder hunter. The Great Plains Hunter has all of the high quality features of our Classic Great Plains Rifle. Factory Assembled. Photo shows percussion model. Shown with optional 57 GPR & 17 AEU sights.