Whisler I agree with you...combustion gasses are not ideal gasses but if, as you mentioned, 2 different materials produce the same relative volume (number of moles) of gas the heat of combustion AND the temp of that gas does NOT have to be the same..Unless you generate the same pressure curve and velocity for a given barrel length and bullet. If the moles of gas produced is the same and the performance of the load is the same then the temperatures of the gasses generated HAVE to be pretty much the same. What am I missing? Is there a chemical engineer in the house? I am an electrical engineer so I don't really know diddly about the bonding energy of nitrocellulose and nitroglycerin but this is a very intersting problem.