You have received some good information on this thread.
TOF suggested dryfirng to acquire a good follow through, and I agree.
A mentor,who taught me to shoot a flint gun, suggested that I dryfire at least 15 minutes a day, every day, for at least a month before firing a live round.
He then insisted that I flash powder in the pan, for at least 15 minutes a day, every day, for a month, prior to firing a live round.
He then insisted that I fire very light loads of 20 gr of powder in a 54 cal rifle, as often as possible, at a range of 20 feet, or so, prior to firing full charge rounds. Don't worry about where the shots impact on the target, as long as they form a group.
While this training regimen sounds extreme, it is much more time and ammunition effective than putzing around with half way measures that take much longer to work through. This method works very well, though I gotta go back to the basics and dry fire, from time to time, to maintain an edge.
It was mentioned that a smaller ball and thick patch might be the answer to your lack of accuracy. And that might be the case, once you get used to shooting flint guns.
I don't know the groove depth of Pedersoli rifles, but I do know that Pedersoli rifles have a reputation for being good shooters, despite spotty quality control, in other areas. The land to land diameter,determined by inserting the shank of a drill bit that mics .321 into the bore. The .321 drill slipped into the bore, but stopped at the raised lettering that mics .323. This suggests a .322 land to land diameter, for this rifle.
The 32 Frontier rifle, mentioned on the "who woulda thunk it" thread, would not shoot well using what is considered "normal" loads for ML rifles. I did try a wide variety of patch/ball combinations, but did not try a really thick patch with smaller diameter ball.
This rifle shot so badly that It set in the closet,without being shot, for over five years. It shot so badly that I couldn't even, with a clear conscious, sell it off to some poor, unsuspecting slob.
Something finally clicked when I found a few .310 diameter balls and a fragment of canvas that happened to mic .020. I thought to myself, "self, why not" and the result is the report on the "Who woulda thunk it" thread.
This gun has finally come into its own with early groups rivaling some of the best shooters I have had the pleasure to own.
So, the moral of these ramblings is, try a smaller ball, with a .020 or thicker patch, and a GOOD patch lube. Spit, Windex, LVL, soap and water, or some other liquid concoction will allow shooting a number of shots without wiping.
Oh, and do funnel the muzzle as Daryl suggests. It does work very well with no loss of accuracy.
God Bless,
J.D. the "Who Woulda thunk it" guy.