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1.
When firing a gun for extended periods of time, the barrel becomes so hot that rounds in the chamber ignite from the ambient heat instead of from the firing pin striking the primer. Cook offs are dangerous because they rarely occur immediately after loading the round and because it's impossible to tell when or if it will happen.
My AR-15 barrel was smoking half-way through the torture test, so I dipped it in water to avoid any potential ammunition cook offs.
by PinkPanzer December 21, 2010