The theory of cutting spiraling grooves inside the barrel of a gun seems to have evolved about 1500 in eastern Germany or Austria. The action of this "rifling" gave the ball a spin which added greatly to its distance and accuracy. By 1600 the bullet was being loaded while seated in patches of greased cloth or thin leather. This provided a tighter fit and helped loosen some of the previous powder fouling as the ball was rammed down, reduced leakage of the ignited charge around the bullet, and gripped the grooves to give the departing ball a better spin.
While the Musket was not an accurate weapon past 50-100 yards, the rifle was extremely accurate to two and possibly three times that distance. This is supported by a statment by British Major George Hanger, who participated in the Burgoyne campaign and subsequently became a prisoner of war after the Battle of Saratoga.
"I have many times asked the American backwoodsman what was the most their best marksmen could do; they have constantly told me that an expert rifleman, provided he can draw good and true sight...can hit the head of a man at 200 yards. I am certain that provided an American rifelman was to get a perfect aim at 300 yards at me standing still, he most undoubtedly would hit me, unless it was a very windy day..."