This is the Indian Wars pistol cartridge pouch for the M1873.  Nearly identical to the American Civil War Cap Box, except with US in oval embossed on the flap.  This economical cap box features an interior lining, brass finial, 2 belt loops on the back and is sewn in white thread.

Started life as a Civil War pattern pouch, was probably unissued, and was then recycled for use during the Indian Wars era. They originally had a wood block to hold the cartridges, but most troopers took them out so the cartridge box would hold a few more cartridges.

Imported.