What is the rate of twist? The .50 caliber is 1-48 I believe and the .54 is 1-66. So I really do not see them shooting minnie ball. Although the .54 might have a chance. Personally I would shoot the roundball and be happy with that. I cast minnie in .50 and .54 and have yet to find a rifle that shoot them (in my collection) satisfactory to hunting accuracy that I demand.