http://en.wikipedia.org/wiki/Rifle

注意Historical overview里面这段话:

The (muzzle-loaded) rifle was originally a sharpshooter's weapon used for targets of opportunity and deliberate aimed fire, first gaining notoriety in warfare during the Seven Years War and American War for Independence through their use by American frontiersmen.

同样根据这篇文字，把光膛(smooth bore)muskets加来福线改良，是18世纪的技术。