like any other natural material, antler will wear and darken with use. The use of ca will insure that the bone will stay as you finished it for years to come.
I routinely powder-coat, but on those occasions when I want a different finish, I use StayBrite spray brass lacquer. It is formulated for brass and should be more durable than other lacquers.
When I finish mine I mount it on the lathe and wet sand with 320, then follow with 600 grit automotive sand paper. Then polish with Brasso. The casing will patina again with wear, but I find most prefer it to a lacquer finish. You can include a jewelry polish cloth with each one you sell, if one prefers to keep the shine alive. I also sell .308 & 3006 kits on my web site. www.thevillageworkshop.net