Fullstock -
There is an artificial gold alloy named "Nu-Gold," which is moderately soft, and which I have used for "gold" rings around barrels. The only problem with it is that it will tarnish and turn black if exposed to black powder residue. The answer is to protect the Nu-Gold with lacquer, or use it in a place where it is not exposed to black powder residue. It is somewhat harder than 24 K gold, about like soft brass. Cost is really cheap.
Bill