I just found out that I was drawn for a depredation hunt for the Bison heard on the North Kaibab Plateau. The tag will be good for any cow or yearling. I haven't decided whether I will ultimately use my bow or my custom muzzleloader. Because of the Condor's presence at the Grand Canyon, I will need to shoot lead-free bullets. I have settled on the 325 grain Barnes 54 cal. Expander MZ bullet. Does anyone have any load data for starting or most accurate load? I suspect 90 to 120 grains??? The stores in my area are out of stock on the Barnes loading manual. BTW: the rifle is a custom .54 caliber side lock percussion with a 34" Green Mountain barrel and a 1:28 twist.