Which statement about the M249's operating mechanism is true?

Which statement about the M249's operating mechanism is true?

• A. It is gas-operated and air-cooled.
• B. It is recoil-operated and water-cooled.
• C. It is gas-operated and water-cooled.
• D. It is electrically fired and air-cooled.

Answer: (A)

The key idea here is that the M249 operates with a gas-driven action while relying on air for cooling. When a round is fired, a portion of the propellant gases is tapped off into a gas port and used to drive a piston that cycles the bolt and re-cocks the weapon, feeding the next round in the belt automatically. This is a gas-operated system, not recoil-operated, so the action isn’t driven by the backward force of the barrel’s recoil. The weapon also uses air cooling, not a water jacket, meaning there’s no water circulation to remove heat; heat is managed by air flow and by changing barrels during sustained fire. It isn’t electrically fired—the trigger system mechanically initiates the firing sequence. All together, gas-operated and air-cooled best describe the M249’s operating mechanism.

The key idea here is that the M249 operates with a gas-driven action while relying on air for cooling. When a round is fired, a portion of the propellant gases is tapped off into a gas port and used to drive a piston that cycles the bolt and re-cocks the weapon, feeding the next round in the belt automatically. This is a gas-operated system, not recoil-operated, so the action isn’t driven by the backward force of the barrel’s recoil. The weapon also uses air cooling, not a water jacket, meaning there’s no water circulation to remove heat; heat is managed by air flow and by changing barrels during sustained fire. It isn’t electrically fired—the trigger system mechanically initiates the firing sequence. All together, gas-operated and air-cooled best describe the M249’s operating mechanism.