It's bit more complicated than that, Ronald. If we start with the basics, i.e., square muzzle, no dings in the crown, a sharp flint or relatively new nipple, a consistent "cheek weld," an experienced shooter, and a proper bench rest, the rest sort of follows. What one needs to do is:
---start with a given RB diameter and stay with it;
---use a 100% cotton patch that is sufficiently tight to allow starting without using a mallet. (As I wrote in response to BP Maniac, patches aren't HC/PC, but they work.);
---start with 70gr. FFg, then
---fire seven - 10 shots at a target you can see clearly @ 25 yd. before changing anything;
---prick the touch hole/vent after every shot + wipe the pan and flint edge as well to minimize hang fires; If you get one, ignore it, but mark your target.
---if no joy, increase the powder charge by 10gr., fire another 7 - 10 shots until you get a tight grouping.
Bare ball shooters can try some of the above as well, but be aware that not all agree on ball diameter and how "bare" the RB should be. Moreover, with BB loads, you'll need to address bore fouling more frequently.
At first the lack of a rear sight sort of annoyed me. Now I've come to prefer it. Additionally, I've tried a truly bore diameter RB (.618") in my 20 ga. trade gun (flintlock) just about every which way, but haven't been able to duplicate the accuracy of a smaller ball (.598" - .603" )with a .014" or .018" patch.
Hope this helps someone out!