I was using a .530 ball, 100 grains 2F, and a pillow ticking patch, .018. Same load in both guns.
In one rifle, the patches are reusable, and the groups were good. That barrel is not coned.
In another, the patches were torn, and the groups were bad. That barrel is coned.
First rifle was a percussion, second was flintlock, so might be part flinching.
In the coned flintlock, I will try .535 and same patch, and see if the patches are reusable, then work on grouping.
Thanks for the advice.