I competed with my Pedersoli Brown Bess Carbine in the mid to late 1970's. The bore size at the muzzle was .754" and I used a .735" ball, the largest size available in those days that was closest to the bore size. I used a greased pillow ticking patch and thus had to use a large diameter short starter.
I used 70 grains of FFFg of Dupont for my accuracy and hunting load. I tried going up 5 grains at a time from there until I hit 95 grains and stopped, because as the charge increased, the group size just got bigger and bigger. My Pedersoli didn't like Fg or FFg, though some folks report good accuracy with either.
When I did my job as the shooter, that carbine would split the ball all day long at either 20 or 25 yards (offhand) on the exposed edge of a double bit axe blade and the two pieces would shatter a clay pigeon on each side of the axe blade. Considering how the ball has to hit the edge of the blade somewhat close to center to split like that, I consider that an excellent example of the carbine's capable accuracy.
I shot off the bench at 25 and 50 yards so I learned how to "Hold Off" for the balls to hit where I wanted at those ranges.
One day we had a trade gun match where the guy who set up the course put a standing buffalo silhouette made for .22 cal and only a bit over 4 inches from head to tail, on the ground. However, he did it at 73 yards, which no one had a "zero" for. I missed by putting a divot into the ground only about 4 inches away and was pretty happy with that.
Again shooting offhand, I got to the point I could hit a one gallon milk jug pretty well centered at 100 yards at least 8 if not 9 times out of 10. I would not shoot a deer at that range from the offhand, but I could keep the ball in the 8-10" circle that is the "killing zone" of a deer IF I used some kind of field rest.
I did not think I then know how to do a trigger job on that carbine, even though I had been doing trigger jobs on large UnCivil War locks for a while and you do a trigger job the exact same way. Had I realized that then and put around a 4 lb trigger on that musket, I may or even probably could have shot the carbine even more accurately.
Gus