A U.S. Army facility that is upgrading older 12.7mm (.50 caliber) M2 noticed that a lot of the guns coming in were quite old. M2 production began in 1921 and some three million have been produced since then. No one every kept track of how long M2s lasted. That question was recently answered when an M2 came in with serial number 324, meaning it was produced during the first year and was 94 years old. The serial number was on the receiver, the heaviest component of the M2 (25.5 kg/55 pounds in the most common version) and the one component that rarely wears out. In contrast the barrel is worn out after about 3,000 rounds and most other components eventually need replacement because of wear or damage. But the receiver is quite a sturdy block of machined metal.
Unfortunately for 324 the extent of the latest M2 upgrades means that it is often considered cheaper to scrap pre-World War II M2s rather than perform a number of accumulated fixes and modifications. But since 324 is the oldest to show up so far it will be displayed as a museum piece.
The M2 has lasted so long because it proved to be the most reliable and durable machine-gun of any caliber ever produced. That durability meant receivers would, if they could avoid battle damage or accidents, serve on and on. The army is seeing proof of that as more and more quite ancient receivers come back for which are mandatory and army-wide upgrades. Because of thus a lot of weapons NCOs have been checking their inventories and as they did that the word began spreading on the Internet (even army armorers have their own online forums) that there were a lot of very old M2 receivers out there.
These discoveries were largely the result of the army, despite budget cuts, coming up with the $356 million needed to upgrade all 45,000 M2HB machine-guns to the M2A1 standard. This upgrade makes the M2 easier and safer to operate. Although this upgrade was first available in 1997, it took over twelve years to convince Congress that this upgrade is a big deal and worth the cost. The basic argument was that because the M2 is one of the most effective weapons the army has, blame for any additional injuries caused by delays in getting all M2s modified would fall on those who refused to provide the cash (about $6,000 per machine-gun).
In early 2011, the U.S. Department of Defense began modifying 6,000 M2s. The M2A1 upgrade includes design changes that eliminate the need to make head space adjustments. This has long been the one big flaw of the M2, as it was easy to do this adjustment incorrectly, which caused the machine-gun to fail when used, often injuring the gunner in the process. While the quick change barrel option was greatly appreciated, the elimination of the head space hassles was even more welcome. Each barrel weighs 10.9 kg (24 pounds). There is also a mounting rail for scopes and a flash suppressor and fixed headspace (which makes the weapons easier to use). In 2010, the Department of Defense also bought 8,000 more M2 machine-gun barrels (for $850 each). Thousands of new M2A1 weapons are also being manufactured but most of the M2A1s will be created by upgrading older weapons.
With a maximum effective range of 2,000 meters and firing 500-600 rounds a minute, the M2 can tear up vehicles as well as enemy troops. The M2 weighs 38 kg (83.8 pounds), plus another 20 kg (44 pounds) if a tripod is used. Most M-2s are mounted on vehicles. Nicknamed "Ma Deuce" by the troops, the M2 has been around so long because it is very good at what it does. Accurate, reliable, rugged, and easy to use, many of the M2s currently in use are decades old and in need of some refurbishment. After the Cold War ended in 1991, the army did not want to build new ones and wasn't sure it could do without the venerable, and very useful, M2.
Efforts to develop a superior replacement for the M2 have, so far, failed. But the Department of Defense keeps trying. In 2008, the Department of Defense gave General Dynamics $9 million to try and develop a lightweight .50 caliber (12.7mm) machine-gun (initially called LW50, then the XM806) that worked. The XM806 was supposed to be ready for troops use by 2012, but that delayed until 2014 or later, and eventually never. Designing and building a lighter and more effective 12.7mm machine-gun has been an elusive goal, and became clear the XM806 would not be acceptable to the troops. While lighter (18 kg/40 pounds) the XM806 has half the rate of fire of the M2 but is said to be safer to use and easier to take apart in the field for cleaning.
Actually, there have been many attempts to design a "new and improved" M2, and all have failed, to one degree or another, in one department or another. The basic problem is that the M2 is sturdy, reliable, and gets the job done to the satisfaction of the users. The XM806 was going to try and get around this by designing a better recoil system and use modern electronic sights so that gunners can get more out of fewer bullets. Most combat veterans prefer the current rate of fire (seven to eight bullets per second) to the slower (four per second) one of the XM806.
What the army was hoping to do with XM806 was not get an M2 replacement but a "good enough" lightweight 12.7mm machine-gun, for those situations where such a weapon is needed. SOCOM (Special Operations Command), for example, has some lightweight vehicles in the works that are too light to carry an M2 but could handle a lighter 12.7mm weapon. The army is not getting a lightweight 12.7mm machine-gun for the troops any time soon. Meanwhile, the army plans to buy over 30,000 new M2s.