Before crossed muskets, the Infantry's insignia was a round military bugle, worn from 1832 to 1875. When the Army went looking for a musket to model the new insignia after in 1922, an officer borrowed an actual 1795 Springfield musket from a private collector's personal gun collection to draw from — General Pershing himself signed off on the final design.
Soft, lightweight combed and ring-spun cotton with the right amount of stretch.