Anyone had any experience with DuraHeat. I was thinking of finishing some suppressors.

http://www.houtsenterprises.net/dur_heat.html

Though I have not used it yet, I would go with Cerakote for high heat areas. Reason being is that a coating that needs heat to cure normally will be more durable and hold up to heat and use better than something that "air" dries. Not that this wont be good but this is just what Ive come to learn. I normally use a IR heat lamp to cure my normal DuraCoat anyway and it really does make the paint harder. Im still working on a CeraKote curing oven but Ive got a few other projects Ive put in front of it....

Since it says that it gets harder when heated, why not cure it with heat?

You can but a coating that is formulated to cure with heat is still strongest...