This year, while excavating the site of the World War II crash of a British Spitfire fighter in an Irish peat bog, six intact Browning Mk 2 (7.62mm/.303 caliber) machine-guns were found and recovered intact. One was cleaned-up and test fired. It still worked.
Peat bogs have a remarkable ability to preserve organic and inorganic material, and in this case also cushioned the impact (at 500 kilometers an hour) of the Spitfire as it hit the side of the hill. This sturdy machine-gun was designed by John Browning, one of the most successful firearm designers of the late 19th and early 20th centuries. His M1917 7.62mm machine-gun was designed during World War I, and evolved into the 7.62mm M1919 and the 12.7mm M2. This last design, the M2, saw no use in World War I, but by the 1920s, its virtues were noted. It was quickly adapted for use in aircraft and saw widespread use on the ground, at sea and in the air during World War II and after. While aircraft use of the M2 lasted about half a century (being replaced by 20mm and larger caliber autocannon), ground troops continue to use it as the M2 ("Ma Deuce"). The M2 has proved so effective, that it's become too good to replace.
Three years ago, the U.S. Army gave up on getting a replacement for the nearly century old M2 machine-gun, at least not anytime soon. However, many of the current ones were wearing out, so the army began replacing over 80 percent of its 36,600 M2 machine-guns, a process expected to take five years, with new M2s. Numerous efforts to develop a replacement for the M2 have failed so far.
For example, six years ago, field testing of the XM-312, the chief contender to replace the M-2, began, in the United States and overseas. The test results were not encouraging, the biggest shortcoming being the low rate of fire (about 260 rounds per minute). This is about half the rate of the M2, and was believed adequate for the 25mm smart shells the XM312 was originally designed for (as the XM307). But for 12.7mm bullets, it didn't impress the troops. There were some reliability problems (the M2 has only one jam per 10,000 rounds), which were believed fixable. The rate-of-fire issue, however, has proved to be more difficult. Meanwhile, a new upgrade for the M2 has been fielded, and Ma Deuce continued to rule the battlefield. The current M2E2 has a quick change barrel, flash hider and lot of small improvements. It is much in demand, but basically the same M2 of 90 years ago.
Originally, the M2 replacement was going to be the M-307, which was designed so it could fire either the computer controlled 25mm "smart shell" of the XM-25, or (by changing the barrel and receiver), 12.7mm caliber ammo. But it was felt that a straight replacement for the M-2 was needed quickly. The original plan was for the troops to begin getting the XM312 in 2008, or sooner. Didn't happen.
The M-2, nicknamed "Ma Deuce" by the troops, has been around so long because it was very good at what it did. Accurate, reliable, rugged and easy to use, many of the M-2s currently in use are decades old, and finally wearing out. The army didn't want to build new ones, and wasn't sure it could do without the venerable, and very useful, Ma Deuce. So it tried to develop a new .50 caliber machine-gun (the XM312). The XM312 weighs 16.4 kg (36 pounds), compared to 22.7 kg (50 pounds) for the M-2, even with the addition of the electronic fire control stuff from the XM307.
The fire control system, especially the range finder, makes the XM312 much more accurate with first shot hits. American troops testing the XM312 also reacted favorably to the lighter weight and fire control electronics. But the lower rate-of-fire on the XM-312 was a deal killer to the many troops who had used the M2 in combat recently.
The 25mm "smart shell" of the M307 is a promising concept that has since been delivered in a shoulder fired weapon (the M-25). But what the troops really want is a heavy shell that can fire through walls, vehicles and take out enemy troops with one bullet. The 12.7mm bullet does all that. For long range grenades, the troops still prefer the 40mm Mk19. The army has 23,000 of these, and many are old and worn out. Not as bad as the M2 situation, but the army is buying 4,600 new ones over the next few years.
Both the M2 and Mk19 have a max range of 2,000 meters. The Mk19 rate of fire is about 350 rounds a minute, and is usually fired in short (a few rounds) bursts of these 19 ounce grenades (which kill or incapacitate most people with six meters of the explosion). The Mk19 is more complex and expensive ($22,000 each) than the M2 ($14,000 each) and jams more frequently. But it is reliable enough to remain popular and in demand.
The M2 has become even more popular with the addition of night and thermal sights. With these, you can spot enemy troops, over a thousand meters away, at night, as they try to sneak up on you. You can eliminate the threat before they get within rifle or RPG range.
The M2 isn't the only firearm to maintain its popularity. For example, the pre-World War II German Mauser and British Lee-Enfield bolt-action rifles continue in use worldwide, mainly for hunting and sniping. The German MG42 light machine-gun of the early 1940s continues to be popular. But the M2 is the only one that continues in military use, largely unchanged for so long.