Heckler & Koch (H&K) XM8 Experimental Assault Rifle

The XM8 is a developmental U.S. military designation and project name for a lightweight assault rifle system that was under development by the United States Army from the late 1990s to early 2000s. The Army worked with the small arms manufacturer Heckler & Koch (H&K) to develop the system to its requirements in the aftermath of the OICW contract, for which H&K had been a subcontractor to ATK. Although there were high hopes that the XM8 would become the Army’s new standard infantry rifle, the project was put on hold in mid 2005, and was formally cancelled on October 31, 2005.

General Dynamics was involved in latter stages and H&K had plans to produce the rifle at a plant in Georgia. H&K was British owned at the start of the project, but was later bought back by a group of German investors. Engineering work was done at facilities in the United States and Germany.

A US Marine weapons instructor holds an XM8 Carbine during the Infantry Operations Chief Symposium in August 2005

Basic overview of XM8 variants.

XM8 testing; One tester is kneeling with an XM8 Carbine and a XM320 (a 40 mm grenade launcher) attached, while the other uses the XM8 sharpshooter (designated marksman) variant.

A prototype XM8 carbine – lacking PCAP device on the side rails. Also has the open ‘duckbill’ rather than ‘birdcage’ style flash suppressor

5.56 x 45mm NATO

Heckler & Koch

6.4 lbs (prototype),
5.7 lbs objective

Overall Length:
33.3 inches (carbine stock extended)

Barrel Length:
Assault: 12.5″
Sharpshooter: 20.0″
Compact: 9.0″
Automatic Rifle: 20.0″

Rate of Fire:
Cyclic – 750 rpm
Sustained – 85 rpm up to 210 rounds

Rate of Twist:
1 in 7 inches

Barrel Life:
20,000 rounds mininum

Muzzle Velocity:
3005 feet/second (M855 Ball) with 20″ barrel
2675 feet/second with 12.5″ barrel
2365 feet/second with 9.0″ barrel

Magazine Capacity:
10 or 30 rounds (magazines can be nested together); 100 round drum available

5 position adjustable for length

Bayonet Lug:
Yes (12.5 & 20″ barrels)

Bipod Interface:
Yes (20″ only)

Sighting System:
Fully integrated red dot with laser illuminator and pointer

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