An interesting demonstration.

A good example of the reason we always carried a spare barrel for the M60 MG (7.62mm) in Vietnam. It doesn't take a long sustained firing, even repeated short bursts will overheat a barrel pretty quickly. I have seen barrels glowing dull orange/red several times. Invariably they are completely shot-out, no longer useful.

Since the suppressor consists of a canister capturing the expanding gases at the muzzle it is understandable that the heat build-up could be extreme.

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