Re: Antique Muzzleloader
Rifling dates to the 15th century, even before the flintlock system. It was not common for military arms because rifles had to be loaded carefully, usually requiring a patch or some method of expanding the ball into the rifling where smooth-bore "muskets" could be loaded just by dumping in powder and ramming the ball.
But rifling was common for hunting and target rifles in Germany for centuries and since it was mainly German gunsmiths who immigrated to the U.S., they naturally brought the idea with them. The result was the American rifle, called either the "Kentucky rifle" from where it was used, or the "Pennsylvania rifle" from where the earliest ones were made.
That rifle, in fact, looks quite a bit like a Pennsylvania rifle, and I thought at first that was what it was.
The barrel is shorter and the caliber larger than the typical American rifle, reflecting both the cost of lead in the (then) colonies and the distances involved for the pioneers; the smaller caliber allowed more shots for a given weight of lead.
Incidentally, it has been often said that German rifles were heavy and clumsy, and that they did not use patches and so needed thick iron ramrods. I submit that that German rifle is light and clearly has a wood ramrod. The patchbox, like the early American ones, has a sliding wood cover, not a brass one like later American rifles.