The Bira gun was a .577/450 Martini–Henry calibre machine gun designed and manufactured in Nepal during the latter part of the 19th century. It was a development of, and based upon, the American Gardner gun. It was double barreled, but fed through an overhead drum magazine similar to the later Lewis gun. The Bira gun was never deployed operationally.
Invented by the Nepalese General Gehendra Shamsher JBR (1871–1905) and similar in some respects to the American Gardner (especially in the reciprocating bolts), the internal mechanism of the Bira Gun is actually quite different in a number of ways, especially as it is hand-crank fired—but the handle is rotated counterclockwise, as this was found more reliable than the usual clockwise rotation of most other mechanical guns such as the Gatling gun and Nordenfeldt gun. Bira Guns were manufactured in 1896–97 and are literally handmade, with few parts from one interchangeable with those on another. They were apparently never used in battle but are interesting artifacts in that they were built at a time when fully automatic machine guns, such as the Maxim, had been developed and were becoming increasingly common.