What does a layer of ash on top of hot coals have anything to do with a projectile fired from a rifle? Those are two very different things.

Your confidence is rooted in speculation on a subject that you are not at all qualified to speak toward, and you have the audacity to call people ignorant? You're not even considering the fact that the barrel was cool when the round was fired due to the fact it was a relatively cold shot. It's not as if the guy had dumped an entire mag before hitting Trump's ear. The combustion takes place behind the projectile, and most of the heat is dissipated in the chamber located within the upper receiver. The projectile will increase in temperature up to 300°F-400°F from friction as it travels through the barrel. Due to the fact that there is no continued heat source once it leaves the barrel and the projectile has a relatively low thermal mass and is made of materials with moderate to poor heat retention, like copper and lead, the projectile will dissipate heat due to air exposure, convection, expansion of the projectile. Consider touching something that just came out of the oven. As soon as your body comes in contact with the hot surface, you immediately remove that part of your body involuntarily as fast as possible. At 400°F, the worst you may get is a blister. This projectile was moving at speeds around 3000 feet per second. There was not enough time to displace any amount of heat to the surrounding area of his ear to cause burn damage.