Originally Posted by
HansTheHobbit
I've seen that video before, and what they're not taking into account is that the rifling was cooked long before the barrels failed. That's the problem with meltdown videos is that they only prove how the rifle would perform under totally unrealistic conditions. Not only can no one carry that much ammo, but no one can fire that fast with any degree of accuracy. I would also have liked to see a temperature comparison at different stages. The heaver barrel didn't droop because of its rigidity, and that may have added a few hundred rounds. I can almost guarantee that the M4A1 got hotter because it cooked off rounds, whereas the M4 didn't. I think there's a really good chance that the throats of both barrels reached critical temp at about the same round count. However, I do think the video clearly demonstrates the folly of the M4 profile. Simply adding a few grams of material behind the gas journal would have kept it going longer, and removing the entire profile around the M4 cut would not have hurt anything. Not only would the barrel be lighter, but it would feel much lighter because of the redistribution of material.
Now normal sustained firing, in short bursts, may prove to be another story. That's what the R&D guy I spoke with didn't really know. He knew for a fact that full auto dumps would destroy the throat of any barrel, even a full bull profile, in the same amount of time, but he didn't know how many rounds a heavier barrel could buy you during normal rates of fire. I would love to see a manufacturer take two barrels, one light and one heavy, put both through the same course to simulate a realistic gunfight, and see how fast the throats get to critical temp.