I use it on most of my smaller projects, i don't have a oven big enough for barrels. I do actions and pistols mostly. The main thing is a good sandblast finish, make sure its clean. Use a respirator when spraying, the overspray is very dangerous. 0ne hour in the 300deg oven, let cool and its ready.
I am looking into the duracoat system, no baking is required, just cure time. two part epoxy system.
Midway USA also sells the same kits.