Gunmetal polishing is the process of polishing the surface of your firearm to achieve a dark gray, semi-reflective finish. This finish can only be achieved on certain firearms, as it requires the stock finish to allow polishing of the high's and non-polishing of the low's of the surface. For example, this finish can be done on Glock's but not Springfield Armory's guns. This finish maintains the texture of the steel while subtly setting your firearm apart from all the others out there. Many times, you will see guns in movies that are grey or silver to make them stand out more, that's Gunmetal.