I've had a few rifles Ceracoated, and the finish is tough as woodpecker lips and absolutely weatherproof. No idea of its long term heat resistance, as I don't shoot enough to get a barrel hot enough to approximate exhaust gas!
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!