I've used Kroil on all kinds of stuff. I've read that Kroil penetrates so well thart it will seep under bore leading allowing the lead to be removed with a tight parch. Seems to work that way for me, too. I have a "soak" that I use to clean my guns; about 1 pint mineral spirits, 1/2 cup Marvels Mystery Oil and about a 1/2 cup of Kroil (I started out equal parts but that doesn't seem necessary). I field strip my guns and soak overnight, then wipe down and run a few parches through the bore. A couple drops of oil here and there (not much needed as the residual oil, M.M.O., lubes most internal parts) and I'm ready to go..