XM8 carbine

The XM8 is the project name for a lightweight, compact assault rifle under development by the German small arms manufacturer Heckler und Koch ("H&K") on behalf of the US Army. The Army's main purpose in contracting for this prototype weapon is to provide replacement options for the venerable but aging M-16 rifle that cost less than the M4 carbine. It was projected to replace the aforementioned rifles starting in 2005, although congressional failure to appropriate funds for a test deployment in 2004 will delay full production.

The XM8 is based on the kinetic energy component of the XM-29 OICW project (under development by Alliant Techsystems with this subsystem provided by H&K). This subsystem was a derivative of the H&K G36 rifle, which was in turn based on the Armalite AR-18. Following the indefinite delay of the OICW project, H&K designed a stand-alone weapon from the kinetic energy component and began marketing it to the U.S. military.

XM8 prototype testing is ongoing with no formal "decision to adopt" by the Army scheduled. In fact, the Army recently issued a "Sources Sought Notice" for a "[n]on-Developmental multi-configurable 5.56mm modular weapon system", with requirements very similar to the XM8 capabilities. Military observers have speculated that (i) this may be a typical procurement requirement prior to committing to a major purchase, (ii) the Army may be opening up competition between the XM8 and the SCAR system (Special Operations Forces Combat Assault Rifle) designed for the U.S. Special Operations Forces (based on the FN FNC), or (iii) the XM8 may have failed in testing and the Army is dropping development altogether.

Should the XM8 be adopted, it would be renamed the M8.

Technical characteristics and variants

The materials used to build the XM8 are almost entirely composites — with the notable exception of the cold hammer forged steel barrel — causing it to be 20% lighter than the M4 (in similar configurations). Four different models have been proposed: a compact PDW (personal defense weapon) with a 9.5 inch barrel (24 cm), a carbine with a 12.5 inch barrel (32 cm), and sniper and SAW variants with 20 inch barrels (51 cm). In addition, accessories such as optical sights, a grenade launcher, and a bipod are integrated using a new system which allows for precision attachment (so that, for example, scopes do not have to be readjusted each time they are attached). Like the M4 and M-16, XM8 is chambered for the standard 5.56 mm NATO round and is normally equipped with a 30-round plastic box magazine. However, this magazine is not compatible with the M4 and M-16's metal magazine. A 100-round dual drum magazine can be used, as well.

One of the XM8's unique features is its modularity. In addition to attachments mentioned above, this modularity allows for quick repairs, barrel length changes, and even caliber changes in the field.

Preliminary tests in desert and arctic conditions have shown XM8 to be an extremely rugged weapon. It is capable of firing 15,000 rounds without cleaning or lubrication and up to 20,000 rounds before barrel replacement. The M16A2 needs to be cleaned at least daily, even if not fired, and has a barrel life of approximately 7,000–8,000 rounds.

However, in terms of size and muzzle velocity, the XM8 is virtually identical to the existing M4 and G36 weapons. In fact, the M4 carbine, with a shorter overall length than the XM8, possesses a longer barrel (14.5 inches) than its potential replacement (12.5 inches). Although a shorter barrel generally results in lower muzzle velocity, H&K claims octagonal rifling will offset the effect of the shorter barrel. Ballistic results to confirm this have not been released to the public.

Along with its basic components, the XM8 will complement the XM29, with such features as identical accessory mounts.

External links

• Modern Firearms (http://world.guns.ru/assault/as61-e.htm)
• XM8 page on HK Defense website (http://www.hkdefense.us/pages/military-le/rifles-carbines/xm8.html)

• U.S. Military Website article on the XM8 (http://www.usmil.com/soldiertech/0,14632,Soldiertech_XM8,,00.html)