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XM8 and it's variants

The XM8 was an expirimental assault rifle which was supposed to replace the M16. while the gun preformed remarkably, the program was canceled after complaints from HK about the non-competitive nature of the program.


The development of the XM8 Lightweight Assault Rifle was initiated by US Army in the 2002, when contract was issued to the Alliant Techsystems Co of USA to study possibilities of development of kinetic energy part of the XM29 OICW weapon into separate lightweight assault rifle, which could, in the case of success, replace the aging M16A2 rifles and M4A1 carbines in US military service. XM8 is being developed by the Heckler-Koch USA, a subsidiary of famous German Heckler-Koch company. According to the present plans, the XM8 should enter full production circa 2005, if not earlier, several years before the XM29 OICW. The XM8 (M8 after its official adoption) should become a standard next generation US forces assault rifle. It will fire all standard 5.56mm NATO ammunition, and, to further decrease the load on the future infantrymen, a new type of 5.56mm ammunition is now being developed. This new ammunition will have composite cases, with brass bases and polymer walls, which will reduce weight of the complete ammunition, while maintaining compatibility with all 5.56mm NATO weapons. Along with 20% weight reduction in the XM8 (compared to the current issue M4A1 carbine), this will be a welcome move for any infantryman, already overloaded by protective, communications and other battle equipment.

The XM8 will be almost similar to the "KE" (kinetic energy) part of the XM29 OICW system, being different mostly in having a telescoped plastic buttstock of adjustable length, and a detachable carrying handle with the sight rail.

As of mid-2004, XM8 now is undergoing wide-scale testing in several units of US Army, and is receiving a positive feedback.

Following several complains about non-competitive procurement of the XM8 system from Heckler-Koch USA, US Army first opened the bidding for contract to other companies, and then, in the July 2005, suddenly suspended the entire OICW Increment 1 program to re-think the entire set of requirements for the possible replacement of current M16 rifles and M4 carbines. These requirements will be re-viewed as Joint Services effort. At the present time, it seems that development of HK XM8 is suspended; it may be resumed if XM8 suit the new US Joint Service Requirements for a new assault rifle system; or, it may not. We will watch this process closely and update this article when new information will be available.

Techinical Description

The XM8 is a derivative of the Heckler-Koch G36 assault rifle, and thus it is almost similar to that rifle in design and functioning. XM8 features a short piston stroke, gas operated action, with rotating bolt locking. Barrels are quick detachable, and planned to be available in several sizes, ranging from 229 mm (9.5 inch) for Compact/PDW version, 318mm (12.5 inch) in Basic version, and two 508mm (20 in) barrels, one for Sharpshooter/Sniper version, and heavier one (along with bipod) for Squad

XM8 rifle in "sharpshooter" (parasniper) configuration. While sight looks similar to red-dot, mounted on other variants, it is of 3.5X magnification; spare magazine is clamped to the right side of the magazine inserted into the rifle.

Automatic Rifle role. The entire construction is modular and built around the polymer receiver with bolt group; Magazine housings could be easily swapped for compatibility with various types of magazines; various buttstocks could be installed in a second for various roles (standard buttstock is a telescoped 5 position adjustable one). Top of the receiver is fitted with proprietary sight rail, which can accept illuminated red-dot (collimator) sight, or any other type of sighting equipment. Detachable forend will be available in various sizes, and could be replaced with XM320 40mm grenade launcher (the improved HK AG36).

Ambidextrous fire controls are mounted on the trigger unit, integral with pistol grip and triggerguard, and in basic configuration are planned to deliver single shots and full auto fire. The G36 -type ambidextrous charging handle is located at the top of the receiver, below the removable carrying handle.


  • Caliber: 5.56x45mm NATO
  • Action: Gas operated, rotating bolt
  • Overall length: 838 mm in basic configuration, butt extended
  • Barrel length: 318 mm in basic configuration; also 229 mm in Compact and 508 mm in Sharpshooter and SAW versions
  • Weight: 2.659 kg empty in basic configuration
  • Rate of fire: ~ 750 rounds per minute
  • Magazine capacity: 30 rounds (STANAG) or 100-rounds double drum in Automatic Rifle/SAW role

See also

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