Most of my rifles are coated. Dura coat works ok, heat the metal first and it sets better. Cerrakote is the **** though, I have had Jose do a few and they always turn out awesome. Haven't had one hydrodipped yet but it looks real good. Guys doing it admit its spendy and needs a clear cerrakote top layer to keep it from wearing.
If its a work gun use krylon, it's going to get beat to **** and paint touches up easily, anywhere. If you are in the woods, use more green. Going to the desert, use more tan....doesn't get any easier or user friendly.