Nepal’s Bira gun is a fascinating steampunk-esque hand-cranked machine gun that is notable for being developed and manufactured at a time when true machine guns were being adopted around the world. It is also notable for being the first (or one of the first) guns to feature an overhead circular magazine, which appeared two decades later on the famous Lewis Gun.
According to Dan Brock, who puts it a lot more colorfully than I will, the British were happy to supply the Nepalese with Martini-Henry rifles and .577/450 ammunition, but were not willing to give them heavier machine gun. A Nepalese general managed to acquire blueprints for the Gardner gun and used those to develop the Bira gun. The overhead magazine held a whopping 120 rounds of .577/450 ammunition The Bira guns were all handmade and parts were not interchangeable between the individual guns. They were never used in combat.
Read more about the history of this gun at Weapons, warfare and industrial idiocy.
Many thanks to Sven for the tip.