What is the barrel length of the M2 .50 caliber machine gun?

The barrel length of the M2 .50 caliber machine gun is indeed 45 inches. This length is significant because it contributes to the weapon's overall performance, including its range and accuracy. A longer barrel allows the propellant gases more time to act on the projectile, leading to higher muzzle velocities and thus greater effective range and lethality.

Additionally, the 45-inch barrel length is a standard measurement that helps in the design and manufacturing of ammunition specifically tailored for use with the M2, ensuring optimal performance. The choice of this length also aids in the balance and handling characteristics of the machine gun, making it easier for Marines to operate in a variety of combat situations.