I always wear a bandana around my neck when hunting. Even tho I carry rope, the bandana not only keeps cold air off my budding neck beard, but could be used as an arm sling if need be. As a bandage, it would be third class but better than nothing, as a tourniquet it would suck... I don't think I could get it tight enough. Speaking of which, I need to look at getting a tourniquet for my go bag and hunting pack!!!
Here's the perfect arm sling (never had to use one as a tourniquet yet knock on wood but I suspect it would excel there as well). Polypro long underwear tops. Simply tie the 2 arms together with a square knot the correct distance so that the arm gets support and it's perfect. Been there done that.
Sorry for thread drift. Sorry to see you head off Andy, this thread is right up your alley, or the next alley over .