May 29, 2007: For the last two years, the U.S. Marine Corps has been shopping for a new light (5.56mm) machine-gun (LMG), to replace the M249, which the army and marines began using in the early 1980s. The marines have had a lot of complaints about the M249 in Iraq (jams from all the dust and sand), and many of the marine M249s are simply wearing out.

The new marine IAR (Infantry Automatic Rifle) must be between 10.5 and 12.5 pounds empty, use a large magazine (100 rounds or more) as well as the standard M-16 30 round magazine. The heavy barrel on the IAR must be able to handle sustained fire of 36-75 rounds a minute. The higher number is the ideal. It must have the standard rail on top for mounting accessories, be resistant to jamming from dust and sand and, in general, be a lot better than the M249. The marines will buy 4,000 weapons initially, and wants to do so soon.

The M249 weighs 15 pounds empty, and has been popular with the troops. But in over two decades, despite several tweaks to the basic design, many complaints have piled up. The marines were not the first ones to take action on a replacement. Three years ago SOCOM (U.S. Special Operations Command) began using the Mk 46 Light Machine Guns. This weapon is a modified version of the American M249 squad automatic weapon (SAW), which is in turn a modified version of a European design from the Belgian firm FN. The Mk 46 is lighter (13 pounds empty, 18 pounds loaded, with 200 rounds, compared to 22 pounds for the M249) and has the rail on top for the quick attachment of sights and such. The lighter weight is accomplished with a newly designed barrel, and removing various bits of hardware SOCOM didn't want. Added is a forward pistol grip and a detachable bipod. SOCOM likes to use the Mk 46 more like a "heavy assault rifle" than a "light machine-gun."

U.S. Army Special Forces pioneered the development of the 5.56mm light machine-gun four decades ago, when they obtained the first experimental models for use in Vietnam. The Special Forces and SEALs were very impressed with the light weight, and heavy firepower, from these weapons. But it took over a decade for the regular army to adopt such a weapon, mainly in response to the success the Russians were having with their own version of the lightweight squad machine-gun.

The army is also making noise about an M249 replacement, and are watching the marine competition with great interest. So far the marines have received interesting proposals from Colt and Ultimax (from Singapore).