Hey, when that rifle was bought the original owner, a sling was a sling was a sling. Especially on mausers with the 'through-the-stock' mounting system, a correct sling was (and largely still is) hard to come by. And, no doubt, as leather is one of the hardest things to preserve, the Izzy slings were cheap, in great shape, and probably the mostly widely available sling that would work.