The smoothbore musket, a weapon of limited range and accuracy that saw service during the American Civil War, it was later on superseded by the Musket which became chief weapon of the American civil war. Firing lines then were more than 500 yards apart and the weapons lacked enough velocity to inflict significant injury, in response to this ammo limitation, attacking troops had to be massed elbow by elbow and attempt an assault, if they were sufficient in number and ran fast enough, then the defensive line couldn't do them much damage.