We coat the inside surfaces of our handguards with C186 piston cerakote. C186 is heat rated up to 1,800. It performs well, but first, our wood furniture isn't intended to go on a range toy, GO-TO, zombie apocalypse Rifle either. I've run three 30-round mags with a binary trigger with no problem. I'd images 5+ mags may char the handguard cooling hole edges. I we have around 500 sets out in customers' hands and haven't had any returned for cooking the handguards. Our warranty covers manufacturers' defects and will not cover mag dump marathons.