The U.S. Marines Corps will complete fielding the new M2A1 .50 caliber heavy machine gun to its combat units by 2018 while the U.S. Army is expected to complete this process in the 2020s.

At close to 40 kg, the improved M2A1 weighs as much as its predecessor, the legacy M2, but features a number of improvements that increase weapon accuracy and crew survivability. The tripod for both weapons weighs close to 60 kg.

Like Us on Facebook

The M2A1 is designed to be more reliable that the standard M2. The M2A1 barrel can fire up to 80,000 rounds before it needs replacing compared to the 25,000 rounds of the M2 barrel.

But more important is the Quick Change Barrel (QCB) of the M2A1 can be changed in about five to seven seconds by just twisting the new carrying handle. The legacy M2 required a far longer and more complex barrel change process.

The M2A1 is equipped with a new slotted flash suppressor that reduces muzzle flash by 95 percent. It also features a modified bolt; a manual trigger block safety and fixed headspace and timing.

The latter advantage reduces the danger to the crew presented by a misaligned barrel after a barrel change, a danger prevalent in the old M2 version.

"Timing" refers to the adjustment of the machine gun so that firing takes place when the recoiling parts are in the correct position for firing.

When a standard M2 had a barrel change, the headspace and timing had to be manually set. Improper adjustment could damage the weapon and cause serious injury to the gunner and his number two. Fixed headspace and timing reduces risk to the two-man crew.

"M2s are the most reliable heavy machine gun," said Maj. Harry Thompson, team lead for General Purpose Weapons at Marine Corps Systems Command.

"The improved M2A1 makes Marines more lethal because they're able to get rounds down range quicker. Marines will have better mobility because of the fixed headspace and timing.

"It's much quicker to move the gun from position to position and put it back into action. Because they're less exposed, Marines will have better survivability too."

The Army began converting its M2HB (Heavy Barrel) machine guns to M2A1s in June 2011. The army has over 54,000 M2s of various variants in its inventory. Of this total, 25,000 have been upgraded to the new M2A1 standard.

The U.S. Marines plan to complete the upgrade of all its ground-mounted M2s to the M2A1 standard by 2018. The Marines plan to have some 3,600 M2A1s fielded by next year.