When firing the M249 (SAW) at a sustained rate of fire of 85 rounds per minute, how often are barrel changes required?

The M249, or Squad Automatic Weapon (SAW), is designed for sustained fire with a specific rate of fire. When operated at a sustained rate of fire of 85 rounds per minute, it is important to understand the heat generation and cooling requirements of the weapon to maintain performance and safety.

In this case, the correct choice indicates that no barrel changes are required when firing at this sustained rate. This is because the M249 can maintain its operational efficiency within specific time frames and conditions without needing an immediate barrel change. Generally, the weapon can endure significant periods of sustained fire before overheating becomes an issue that necessitates a barrel change. Barrel changes are typically required after firing for extended periods at a rapid rate, or if the firing conditions produce excessive heat.

By adhering to the guidelines for sustained fire, the operator can effectively manage the heat buildup within the weapon system, thus eliminating the necessity for barrel changes under the stated conditions.