When firing the M240B at a sustained rate of fire, how often must you change the barrel?

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When firing the M240B at a sustained rate of fire, it is essential to change the barrel every 10 minutes to prevent overheating and ensure the weapon operates effectively. The sustained rate of fire for the M240B is typically around 100 rounds per minute, which can lead to excessive heat buildup in the barrel. If the barrel is not changed at regular intervals, it can result in barrel damage or even a malfunction.

Changing the barrel every 10 minutes helps maintain the weapon's reliability and extends its lifespan by allowing it to cool and reducing the risk of cook-offs, where the rounds can unintentionally fire due to the heat. This procedure is a critical component of the weapon's operational guidelines, ensuring that troops can maintain effective fire while minimizing the risks associated with overheating.