Once at a .50 range in Germany, we became aware that there was a LOT of firing coming from one particular weapon, while the rest of us had paused. Found out later, an office monkey who had tagged along had linked about 400 rds, and tried to fire them continuously. When the 1sg confronted him to ask why he would do such a thing, he replied that the B-17 gunners used a lot more ammo than that and they were ok to do it. We explained to him, they did NOT EVER squeeze off that many rounds without pause, and they had air-cooled barrels on their guns. We took off the barrel, (With mits, of course,) and when it finally cooled off, it had turned blue. I'm not enough of an expert to know what the exact terms for this condition, but we knew that we weren't going to use it anymore. We turned it in, lots of paperwork.
An old marine I grew up with told me that in Korea facing the Chinese, once he fired the .50 on his Sherman until the barrel glowed in the night, and then suddenly, the rifling shot out the end. He said he used the mit, tossed the old barrel, screwed a new one in all the way, backed it off two clicks, and kept on firing.
