so I see you red the translation of the '' trois mousquetaires'' (aka three musqueteers)
if you feel bad about it just tell you it's French and you'll be alrigth.
if you want the real answer: musqueteer is a traduction of the french word: mousquetaire and the french musqueteer were none but gentlemen of the middle class nobility so using a musket was reserved only in battle.
they'll use musket in a battle on a farm after a while