.410 Musket
As SMELLIE has suggested, a round ball might be more appropriate, IN A SMOOTH BORE FIREARM. Round balls fly truer, and have a bit more accuracy. Slugs or bullets tend to turn end over end, and end up going through the target sideways or keyhole, as it is known. Well worn rifle barrels are famous for doing this.
What you are referring to as paper patching is actually a Sabot. This is a larger diameter wrap or carrier that holds a projectile and fills the bore. Sabots are designed for shooting in smooth bores, which a .410 Musket is. They can be small, (of rifle calibre) or large enough to be shot from tank cannons.
Paper patching, is better thought of as paper jackets. It is a way for lead projectiles to be fired without having the powder deform the lead projectile when fired. Paper patches (or jackets) are thin paper usually wrapped twice around the projectile and cover the base. They are intended for a rifled bore, and to engage the rifling to impart a spin on the bullet. I have successfully fired soft lead cast bullets designed for the 30-06 (.308) calibre in the .303 British with accuracy equal to or better than Mark 7 Ball ammunition.
Faster burning powders should be appropriate, and SMELLIE has suggested an initial loading. Accuracy will probably be hit-and-miss, (Pun intended), so do not expect too much in the way of target or precision groups. It's a fun thing.
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