Arma-coat is best adhered to a finish that is bead blasted, parkerized, then Arma-coated. Contact "murdoc" (Barrett Arms of Thorhild, Alberta). He can do the work at a reasonable cost. He also oven cures the finish so it comes to you ready for action. You can also do it yourself, but at the very least, the surface needs to be FREE of any oil residue, even finger prints. If the finish is already "matte blued", then the Arma-coat will adhere very nicely. Personally, it's worth the few hundred dollars to have it professionally done. I've had 4 rifles and numerous parts Arma-coated by Barrett, and all have held up incredibly well. 100% weather-proof and rust free in some of the most horrendous outdoor conditions. Just keep the bore lightly oiled and you're covered. My stainless rifles have rusted in the same environments.