How hot does a barrel get? The only reliable figure I could find was a U.S. Army Ordnance report from 1975, which dealt with heating in the M-16 rifle. (None of the usual websites seemed to know about civilian guns. The typical answer was “hotter than two rats screwing in a woolen bag,” which is evocative, but not scientific.) The Army report is fully comprehensible only to military minds, but I was able to get a couple facts from it:  After 280 rounds, fired at the rate of one round per second, the temperature at the hottest point on the barrel was 1,300 degrees F.  The hottest point on the barrel was 6 inches ahead of the bolt face. As the rifle heated up, that point shifted rearward to 4 inches.