Grandpa passed last year and Grandma has asked me to sell his guns. This one has got me stumped! I am trying to figure out what it is, where it's from, and when it was made. It has an octagon barrel. It is a single shot with 2 triggers, one to cock it and one to fire. It has markings on the barrel that say "KH" "GBU" "44" and some other markings. Any help would be appreciated! Mike