I was taught that whenever the hammer ( frizzen) was drawn the weapon would be in "Battery". I only refer to "Battery" now when I refer to a muzzle loading weapon and I really cannot say why. I bet when the Germaninfluence introduced the Jaeger in colonial America is when the terminology began to be interpreted differently. To this day, in Northern Berks county PA the old Germanic language is still spoken and handed down to the younger generations. Having lived and worked in the vicinity of the local historic gun-builders of the region I can say the that the language has become modern speak and has transgressed even with the "English". If you have an opportunity to visit the gun-makers fair in Kempton PA. or visit Mr. Dixon's shop you can experience the local culture. Some of the early settlers were massacred by the Indians and began to spread out, some expanding to take advantage of the frontier taking their weapon making skills with them and surely when introducing their wares to the other non english speaking peoples near them the term "rifle" broke the language barrier as well.