ARTICLE

February 2004

Army Tests New Rifle That Could Replace M16, M4

by Harold Kennedy

The U.S. Army is testing a new, lightweight assault rifle that employs many of the technologies already developed for the planned objective individual combat weapon, which would combine an infantry rifle with a grenade launcher. The service decided to go ahead with this latest rifle—known as the XM8 Lightweight Modular Weapon System—after repeated delays in the OICW program.

If the tests are successful, the XM8 eventually could replace the Vietnam-era M16 rifle and M4 carbine as the standard weapon for infantry soldiers, according to Army Lt. Col. Mathew T. Clarke. First, however, it has to pass strenuous testing by the Army.

So far, Clarke said, he is impressed by the XM8. “I’m very excited about how the weapon has performed,” he told National Defense.

Clarke is program manager for individual weapons at the Army’s Armament Research, Development and Engineering Center, at Picatinny Arsenal, N.J.

Under Clarke’s supervision, the Army this past fall took possession of 30 prototypes of the XM8—the first of 200 that it has ordered—and began test firing them at the Aberdeen Proving Grounds in Maryland.

In December, the XM8 was “doing very well thus far” in the tests, said Jodie Daubert, a spokesperson for the program manager’s office. “Yesterday, while we were at Aberdeen, a retired soldier—who hadn’t picked up a weapon in six years—picked up the XM8, during the live fire, and hit the target with his first shot,” she said.

“In fact, he hit the target with every shot. And that was from a standing position at 300 meters.”

The Army agreed in October 2002, to pay $5 million for a team headed by ATK Integrated Defense Company, of Plymouth, Minn., to develop the weapon rapidly. The team included Heckler & Koch Defense Inc., of Sterling Va., as the weapon’s designer and manufacturer. HK Defense is a subsidiary of Heckler & Koch GmbH, of Oberndorf, Germany.

The agreement was a modification of an existing $105 million contract for the same team to build the OICW, now known as the XM29. Under development since the mid-1990s, the XM29 is two weapons in one—a rifle that fires a 5.56 mm kinetic-energy round and a grenade launcher that expends a 20 mm air-bursting munition.

The XM29 is designed to replace the M16 and M4. Both also fire a 5.56 mm munition, and they can be fitted with an attached M203 40 mm grenade launcher.

The XM29’s development is progressing, but it is overweight and years behind schedule. Originally, the weapon was supposed to begin production in 2005, but that date now has been pushed back to “the end of fiscal year 2010,” said Clarke.

Designers have struggled to fine-tune the air-bursting technology and to reduce the weapon’s weight. The original prototype of the XM29 weighed 18 pounds, which Army officials said was too heavy for an infantryman to carry into combat. By 2010, plans call for the weight to drop to 15.5 pounds.

“We have a huge weight restraint,” Clarke said. “Quite frankly, we have to wait for technology to catch up.”

As a result of the delays, Clarke embarked on a new plan. “After I got here and reviewed our acquisition strategy,” he said, “I decided to change from an evolutionary approach to spiral development.”

Instead of developing the XM29 gradually, Clarke decided to speed up development of its components as separate weapons. The rifle portion would be developed as the XM8, and the grenade launcher would become the XM25 Air Burst Weapon.

The XM25 will fire a 25 mm air-bursting munition, rather than the 20 mm planned for the XM29, said Col. Michael J. Smith, program manager for soldier weapons.

In fact, he said, the Army is developing a 25 mm thermobaric round that it plans eventually to fire from the XM25. Such a round contains an explosive that reacts with oxygen inside a targeted area, such as a cave or a building, causing intense destruction inside the target. The Army successfully test-fired a thermobaric round in September, using an XM307 Advanced Crew Served Weapon.

The XM25, however, is “much more challenging than the XM8,” Smith said. A prototype is under construction and scheduled to begin testing this summer, he said.

The XM8 is a modular weapon system, explained Jim Schatz, HK’s military sales manager. It is being developed in four variants, including a carbine, sharpshooter, automatic rifle and compact carbine. The lightest version, the carbine, weighs 6.4 pounds, compared to 8.85 pounds for a similarly equipped M4, which is a shortened version of the M16.

XM8 parts—such as the barrel, butt stock, magazine, sighting system and carrying handle—can be changed easily and quickly to meet the requirements of the different variants, Schatz said. Barrel lengths range from nine inches for a compact carbine, to 12.5 inches for a standard carbine, to 20 inches for the sharpshooter version.

The automatic rifle variant features a heavier 20-inch barrel for sustained fire, a folding bipod and a 100-round drum magazine. Other magazines have capacities of 10 and 30 rounds. They can be nested together for ease of reloading.

Unlike the current M4 and M16, the XM8 does not introduce propellant gases and the associated carbon fouling back into the weapon’s receiver during firing, Clarke said. This greatly increases the reliability of the XM8, and it reduces cleaning time by as much as 70 percent, he said.

The weapon can fire more than 15,000 rounds without lubrication or cleaning even in austere battlefield environments. “It works better in a desert environment,” Clarke said.

A cold-hammer forged barrel enables the XM8 to fire at least 20,000 rounds without service and provides more protection for the shooter should the bore become obstructed during firing, he said.

A battery-powered sight includes a red-dot, close-combat optic; infrared laser aimer and laser illuminator with a backup etched reticle. The sight is factory “zeroed”—adjusted—and does not require constant re-zeroing in the field, as is the case with current rail-mounted targeting device, Schatz said.

To allow targeting devices to be attached quickly to the XM8, flush-mounted attachment points are located on the weapon’s handguard and receiver. Unlike the Picatinny 1913 rails that attach to the M4 and M16, the XM8’s attachment points are built in and do not add weight, bulk and cost to the weapon.

Additional weapons—such as the new XM320 single-shot, 40 mm grenade launcher and the 12 gauge Lightweight Shotgun System—can be installed in the field, without tools. (sidebar p. 42)

The XM8 has fully ambidextrous operating controls, Clarke said. The controls include a centrally located charging handle, magazine release, bolt catch, safety and selector lever with semi and full automatic modes of fire, and release lever for the multiple-position collapsible butt stock.

The controls allow the shooter to keep a firing hand on the pistol grip and the weapon in the firing position at all times, while the non-firing hand actuates the charging handle and magazine during loading and clearing.

Major components are produced from high-strength, fiber-reinforced polymer materials that can be molded in almost any color, including forest green, desert tan, arctic white, urban blue or covert black. Surfaces that the shooter touches are fitted with non-slip materials to increase comfort and ability to hold on to the weapon in all weather conditions.

The XM8 is being designed at HK’s facility in Virginia. If the Army accepts it, the weapon will be produced and assembled at a new HK manufacturing plant to be built in Columbus, Ga., near the Army’s Fort Benning.

Plans, announced in August, call for the 75,000 square-foot factory to incorporate state-of-the-art manufacturing processes, including cold-hammer forging and advanced polymer molding. Initially, the factory will create about 200 jobs and $25 million in capital investment in Columbus, said Peter Simon, HK’s U.S. vice president. That number, however, could grow “as some of our U.S.-based design and development projects mature into production,” he said.

In addition to the XM8, HK hopes the plant will produce the planned Special Operations Forces Combat Assault Rifle and the USP Compact .40 caliber pistol, used by many federal, state and local law enforcement agencies. (related story p. 43) The company also may shift some of its Design and Engineering Office from Sterling to Columbus, Simon said.

The Army plans to begin operational testing of the XM8 in the fourth quarter of fiscal year 2005. Fielding is scheduled for early 2007. “That’s a very fast-paced schedule,” Clarke said.

If the XM8 is fielded to the entire active-duty Army, National Guard and reserves, more than a million weapons would be required.

Back To Top