You'd think it would be easy to swing by the sporting goods store and pick up a good stock mounted cartridge holder. After too many disappointing trips, we put together the one we wanted. Hypalon construction is light weight, tough, won't soak or stretch, and is also non-slip. We used high quality 2" elastic, added a fixed butt loop to completely prevent walking forward, and a windowed slot on the offside for a data card.