Notwithstanding the rumors of Civil War era carbines with attached coffee-grinders to help soldiers with their bean-juice, the grinder on on this 1859 "Coffee Mill" Sharps Carbine is thought to have been used for corn or wheat.
An excellent history of coffee's role in the Civil War by Jon Grinspan has kindled interest in guns that doubled as coffee-mills. But the curator's notes from the Springfield Armory Museum for this piece notes that tests by an historian suggest that it was not used for that purpose.
Manufactured by Sharps Rifle Co., Hartford, Ct. – Model 1859 Sharps single-shot breechloading carbine with iron furniture and iron patchbox. grinder attachment designed by Lt. Col. Walter King who was on "detached service" from the 4th Missouri State Militia Cavalry for all of 1864 and 1865. Stock shows some fire damage. Grinder may be incomplete, at least one screw missing. There are no more than twelve of these known today. Long thought to be used for grinding coffee, the general consensus is now they were used for grinding corn or wheat. Tests done by Mr. Andrew Lustyik concluded that grinder was in fact unsuited for coffee. NPS Historian Jim Ogden of Chickamauga National Battlefield came to the same conclusion in tests he conducted on the "Coffee Mill" Sharps in that collection.