In the United States Congress is putting a lot of pressure on the military to develop new weapons for the infantry. Machine-guns are a particular problem and have been for over half a century. For example, the flawed M-60 light machine-gun replaced the BAR (an automatic rifle with a heavy barrel, a 20 round magazine, and used as a light machine-gun) and M1919 light machine-gun (which was too heavy to be portable) in the 1960s. The BAR and M1919 had been around since the 1920s. The M-60 has since been replaced by several more capable models and more are on the way. But the army has had a very hard time replacing the M-2 heavy (12.7mm/.50 caliber) machine-gun. This one also first appeared in the 1920s, but all efforts to replace it have failed. That has not halted efforts to come up with a better M-2.
Meanwhile, existing M-2s continue to undergo improvements. Last year the army convinced Congress to provide the cash to upgrade all 45,000 M2HB 12.7mm (.50 caliber) machine-guns to the M2A1 standard. This upgrade makes the M2 easier and safer to operate. Congress was convinced that this upgrade was a big deal because the M2 is one of the most effective weapons the army has and 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).
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.
Three years ago the U.S. Department of Defense began modifying the first 6,000 M2s. This included supplying additional barrels for the quick barrel change feature. 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). Three years ago the Department of Defense also bought 8,000 more M2 machine-gun barrels (for $850 each). This M2A1 version is the latest upgrade for the M2 so far. Another 5,080 new M2A1 weapons were manufactured, to replace combat losses and elderly M2s that are just all worn out.
With a maximum effective range of 2,000 meters and a rate of fire of about 500-600 rounds a minute, the M2 can tear up vehicles as well as enemy infantry. 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. Since 1921 about three million have been built.
The M2, nicknamed "Ma Deuce" by the troops, has been around so long because it is very good at what it does. Accurate, reliable, rugged, and easy to use, many of the M-2s currently in use are decades old and finally wearing out. The army doesn't 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 have, so far, failed.
There have been a growing number of efforts to build a better M2. Five years ago the U.S. 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 works. The XM806 was supposed to be ready for troop use by 2012, but that was delayed a year and then the XM806 was cancelled last year. Designing and building a lighter and more effective 12.7mm machine-gun has been an elusive goal, and it eventually became apparent that the XM806 would not pass muster with the troops. While lighter (18 kg/40 pounds) the XM806 had half the rate of fire of the M2 and was supposed to be safer to use and easier to take apart in the field for cleaning. Not all the improvements worked and the XM806 turned out not to be good enough to replace the M2.
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 tried to use a better recoil system and modern electronic sights so that gunners can get more out of fewer bullets. Most combat veterans prefer the current rate of fire (7-8 bullets per second) to the slower (4 per second) one of the XM806.