Misselier - concerning Riflling of gun barrels; what you heard was correct. A gunsmith would hand forge a barrel as you described. And yes they did cut grooves into the bore of the barrel as you describe,but there were different type weapons for different uses. There is an old,but great video on VHS, and maybe DVD from 1969 of Master Gunsmith-Wallace Gusler of Williamsburg,VA gunshop hand forging not only a gun barrel and rifling it, but hand forging each part & all the hardware. The video is called,"Gunsmith of Williamsburg". If you can get a copy, watch it,as it shows everything you are asking about. Wallace Gusler uses period tools to construct the barrel exactly as they did in the colonial days. And if you were to order a colonial rifle built by them, it will cost between $20,000 & $40,000 according to a Virginia Gunsmith I once talked too, and with that said, there's even a 4 year waiting period once you order. But to finnish answering your questions;there were civilian guns, and military guns, and also there were civilian Rifles used in the Revolutionary War as I am a direct ancestor of a Revolutionary War Rifleman from Loudon County,VA. Although everyone is familiar with the battle formations of the time with companies of Musketmen lined up to fire at each other, due to the lack of accuacy of the smoothbore Musket; not many know that on each end of the front line were companies of Riflemen. Each Regiment had 10 companies, and 3 of those companies were Rifle Companies. My ancestor fought in the 3rd Company of the 3rd Virginia Regiment under Capt. Charles West. In order to be able to enlist in a Rifle Company, you had to prove your skills. The usual test was that they would set up a life size silloette of a British Officer and some say even King George himself, and one had to load their Rifle; shoot and hit it in the head or heart some say, at 100 yards the first shot. If you missed; you ended up enlisting in a Musket Company. And each Rifleman had to bring with him in Virginia 3 items. His best Rifle, a blanket and a tomahawk. The reason for the tomahawk was because civilian rifles had not bayonet lug on the end of the barrels being a civilian weapon, thus they used the tomahawk for close contact fighting. Also the civilian hunting weapons,which most comoner who lived away from cities had in order to both hunt for food on occasion, and also to ward off Indian attacks were the smooth bore long arm called the Fowler,perhaps because you used it to shoot fowl & small game. The Fowler could either be loaded with a solid round shot, or many small shot and shot much as todays shotgun, which made the Fowler a versitle hunting weapon. Then there was the hunting Rifle, which could hit game at loner ranges, or Indians, or during the Revolutionary War, British Officers. My ancestor; being a Rifleman had a slightly better chance of surviving the Revolutionary War since he was on the ends of each line in battle among other Riflemen who moved swiftly to out flank the British line hopefully, and could hit their targets/British Officers at much greater distances. And thus, my ancestor survived the first year of the Revolutionary War, then after fulfilling his 1 year obligation, married and moved to North Carolina and survived the war to old age.
Well, I hope this additional information helps you to understand that they did in fact have rifled long arms made in the way you describe and for specific purposes.
God bless,
Jim