Guns.com has an article on this interesting carbine. The idea was to have a mill so a soldier could grind up wheat or oats while moving. It somehow got the nickname 'Coffee grinder Sharps carbine' but it can't grind coffee beans.
http://www.guns.com/2016/02/05/the-coffee-grinder-sharps-carbine-with-a-mill-right-in-the-stock-10-photos/
From: Guns.com
