I have found that most black powder guns can be very finicky when shooting different bullets. I have shot the maxi balls and hunters in different guns. They shot very good in my NEF .50 cal. ( 1 in 28) and also my Cabela's Hawkens Carbine (1 in 24). However, when I tried them in my ex-Encore, they shot horribly. I couldn't get them to group to save my life. I never tried to measure them for correctness in design though.
I still want to shoot the Great Plains bullet in the carbine. I expect it to perform very well. I would also like to shoot the R.E.A.L bullet. I would like to mold my own bullets, but it is hard to find guys who have these other different bullets in the .54 caliber. I only wish the carbine could shoot PRB bullets, but with the 1 in 24 twist that makes it impossible I guess.
I must say that the Encore (junk) would only shoot the T/C SST bullets and pretty much nothing else. That is why I got rid of it. For now I am in love with my new carbine.