I'm guessing that it's a hunting bag of some kind. May be one of a kind that someone made for a special purpose to suite themselves. Hard to tell but the loops look of rifle cartridge size, if shotgun size I'd say for huntings birds.
Just had an idea. With the flap being Beaver, having cartridge loops inside, and the thongs hanging down with rings on the ends, I'm wondering if it belonged to a trapper. Those rings would be handy to hang small traps from. Just a thought.