Availability of the proper firearm could determine life or death on the colonial frontier, and gradual rifle modifications soon began to appear among the new gunsmiths in Pennsylvania. For greater accuracy, the short barrels were lengthened (to consume all of the powder charge and provide a longer aiming span); for economy of lead and lighter weight, the bore was reduced; for a flatter trajectory, a higher ratio of powder to ball evolved; and for better balance in carrying through rough country, the stock was thinned and reshaped. By 1770, the American rifle destined for use in the Revolutionary War had acquired many of its basic characteristics: a barrel length usually over 40 inches; a bore averaging .40 to .60 caliber (with seven or eight grooves); a long thin stock extending to the muzzle; a flat-style lock having a bridleless pan and gooseneck cock; an elevated handgrip on the rear of the trigger guard; raised carving around many of the fittings; and a patch box with a wooden, iron, or simple brass cover. The picturesque "Roman nose" butt generally associated with early American rifles appeard mostly after the War for Independence.
This amazing weapon, which had an accurate range of up to three hundred yards (i.e. more than three times the average musket), was actually limited to specialized service in the Continental Army. It was primarily a civilian arm, and its slow rate of fire and the inability to mount a bayonet made it impractical for use in the open field tactics of the day. However, in the hands of skirmishers and light troops operating in wooded areas, it proved to be extremely valuable.