How often should the barrel of the M240B be changed when firing at the sustained rate?

When firing the M240B at the sustained rate, the barrel should be changed every 10 minutes to maintain optimal performance and prevent overheating. This guideline is crucial because sustained fire can significantly elevate the temperature of the barrel, leading to malfunctions or even damage. The 10-minute interval allows the barrel to cool adequately while ensuring a consistent rate of fire.

It is essential for operators to adhere to this protocol to ensure the weapon's reliability and effectiveness on the battlefield. Maintaining the barrel's longevity through proper timing of changes is key to effective operational readiness and minimizes the risk of potential weapon failure during critical moments.