Sharp's patent breech loading carbine, a US issue rifle. It is a .52 rimfire. The barrel slides forward for loading. The serial number is 209.
There is a cream, rectangular label which says: 'Sharps + Hankins. .45". American carbine. Breechloading single-shot with sliding breech.'
A rare and interesting piece, in unusually good condition. As a .52 rimfire, it is an antique. It could possibly have been on limited purchase during the Civil War.