The crossword solution for the term 'Musket Ending' is 'EER', which stands for 'Enfield Pattern 1853 Rifle-Musket'. This was a British muzzle-loading rifle-musket used by the British Army during the 19th century. It was the second most widely used longarm in the British Empire after the Brown Bess musket. The Enfield Pattern 1853 Rifle-Musket was the standard infantry weapon of the British Army from 1853 until 1867, when it was replaced by the Snider-Enfield.