Aren't you still measuring the temp of the air? With the thermocouple system you are getting the temp inside the bullet. I have been using the thermocouple for a couple of years now. I do hi-tek and powdercoat. My bullets are better doing it this way. Again, thanks to Ausglock who dreamed this up. He is the tester for hi-tek and has probably coated more bullets than anybody on the planet.