I have experience of the Parker-Hale Volunteer with Henry rifling. I understand that the Pedersoli is of similar pitch rifling but don’t know what form it takes. Some answers to your questions and related to target shooting only.
1. What distance are you seeking to shoot at? Some use these rifles with light loads of FFFg and get good accuracy at 100m. If I was starting load development with this rifle I would be looking at FFg or 1.5FG (Swiss No. 3 or 4 respectively), but my interests are primarily long range.
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3. For best accuracy these rifles are usually cleaned between shots. You can try with the bullet seated directly on the powder, but will need to clean to the breech - usually best to cap off again after wiping to ensure flash hole is clear. Alternatively, a snug fitting card wad loaded on top of the powder can be used. You can then wipe the bore and seat the bullet (the wad stops moisture getting to the powder). That’s how I fired my Volunteer. A lubed felt wad could be tried to manage fouling. Wads can help protect the bullet base.
4. 460 grain is quite light, but should be good for short range. Getting out further I would be looking for around 530 grains.
5. I set an MLAGB record score at 600 yards with my P-H Volunteer that remained in place for several years. They can reach out to 1000 yards but aren’t often seen in matches, generally being outclassed by the half-stocked match rifles (eg. Pedersoli Gibbs) that have a faster rate of twist for their rifling.
6. To get the best out of them, consider in due course fitting aperture sights. Contemporary sights have elevation on the rearsight and windage on the foresight. Beware of ‘Soule’ type sights; with their windage adjustment they are mounted quite high and you may not be able to use them at short range - if ‘spirit of the original’ is a factor, Soule sights are from the breech loading era and post date the muzzle loading military target rifle by two decades or more. Nipples on these rifles can burn out very quickly - the solution today, as in the 19thC was a platinum lined nipple. As the flash hole erodes blow back can cause the hammer to lift, even fractionally you will get pressure loss and accuracy will suffer, in extreme cases the hammer can be blown right back.
Browse the
Long Range Muzzle Loading section on my web site for more general guidance.
David