Originally Posted by
CrAzYLoCaL
If your shoe laces aren't tight brass could fall in there and burn your feet!
Some calibers have more bang than others.. more powder more heat. Some cases are thinner than others. There's so many different factors, so try not to split any hairs here. But back to ARs, they run hotter because of their design obviously, and that gas being dumped into the upper is constantly heating up the rounds in the magazine, inherently making every round hotter to begin with, before firing. Savi?