One way to extend the life of your S&W revolver is to take a carpenter's or artist's pencil (the ones with soft, rectangular shaped leads), and rub it on the topstrap immediately above the bbl. This is because of the phenomenon of top strap cutting. It used to be thought that this was due to the hot gas escaping from the bbl. / cyl. gap, but it has been shown that the problem was actually unburned powder grains in the gas acting almost as a sandblaster does. The graphite/polymer layer deposited by the pencil will effectively counter this phenomenon.