July 31, 2007: Two years ago, field testing of the XM-312, the replacement for the eighty year old, .50 caliber (12.7mm) M-2 ("Ma Deuce") machine-gun, began, in the United States and overseas. Then, nothing. That's because 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, which could be fixed. 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 still rules the battlefield. The new M2E2 has a quick change barrel, flash hider and lot of small improvements. It is much in demand.

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), .50 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.

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 doesn't want to build new ones, and wasn't sure it could do without the venerable, and very useful, Ma Deuce. So it ended up going ahead with the plan to build a new .50 caliber machine-gun (the XM312). Actually, the new Ma Deuce is basically the XM307, but without the ability to fire 25mm rounds. The XM312 weighs 36 pounds (compared to 50 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, than the M-2. American troops have been testing the XM312 in the United States and Germany, and have also reacted favorably to the lighter weight of the XM-312. The lighter XM312 will be easier for infantry to manhandle into position (along with its tripod mount.) But the lower rate-of-fire on the XM-312 was particularly disappointing to the many troops who had used the M2 in combat recently.