This bag is a type believed to have been developed by the Canadian Métis. During the War of 1812, British infantry troops wore crossed leather belts, one to hold the cartridge 1box on the right side and one to hold the bayonet in its sheath on the left. These beaded bags first appeared just after that time; the oldest collected example known was obtained in 1833.
Most of them have a second strap for the powder horn, beaded in a complementary but non-matching pattern (I have seen only one outfit that does match). However, in its westernmost dispersion, the Yukon River of Alaska, hunters used the bag for bullets and caps and wore it alone and in front. This example was made around 1880 in northwestern Canada or the interior of Alaska.
Illustrated in Spirits in the Art, by James A. Hanson, p-259.