Old Handmade Gray Painted Toy Gun

I think most likely a kid made this, and I believe it is a rubber band gun, though I'm not entirely sure how exactly it worked. (I believe a rubber band was stretched from the end of the barrel and through the hole in front of the trigger, but I don't quite get the release.) Anyway, I just love it as an object now I think, super folky but also pretty elegant, with a great old well worn matte gray painted surface.

11 1/8" l x 4 " t x 7/8" thick and in good condition, with trigger that moves.