XM8 rifle
Encyclopedia
Assault rifle
An assault rifle is a selective fire rifle that uses an intermediate cartridge and a detachable magazine. Assault rifles are the standard infantry weapons in most modern armies...
system that was under development by the United States Army
United States Army
The United States Army is the main branch of the United States Armed Forces responsible for land-based military operations. It is the largest and oldest established branch of the U.S. military, and is one of seven U.S. uniformed services...
from the late 1990s to early 2000s. The Army worked with the German
Germany
Germany , officially the Federal Republic of Germany , is a federal parliamentary republic in Europe. The country consists of 16 states while the capital and largest city is Berlin. Germany covers an area of 357,021 km2 and has a largely temperate seasonal climate...
small arms
Small arms
Small arms is a term of art used by armed forces to denote infantry weapons an individual soldier may carry. The description is usually limited to revolvers, pistols, submachine guns, carbines, assault rifles, battle rifles, multiple barrel firearms, sniper rifles, squad automatic weapons, light...
manufacturer Heckler & Koch
Heckler & Koch
Heckler & Koch GmbH is a German defense manufacturing company that produces various small arms. Some of their products include the SA80, MP5 submachine gun, G3 automatic rifle, the G36 assault rifle, the HK 416, the MP7 personal defense weapon, the USP series of handguns, and the high-precision...
(H&K) to develop the system to its requirements in the aftermath of the Objective Individual Combat Weapon
Objective Individual Combat Weapon program
The Objective Individual Combat Weapon or OICW was the next-generation service rifle competition that was under development as part of the United States Army OICW program; the program was eventually discontinued without bringing the weapon out of the prototype phase...
(OICW) contract, for which H&K had been a subcontractor to ATK
Alliant Techsystems
Alliant Techsystems Inc., most commonly known by its ticker symbol, ', is one of the largest aerospace and defense companies in the United States with more than 18,000 employees in 22 states, Puerto Rico and internationally, and 2010 revenues in excess of an estimated...
. Although there were high hopes that the XM8 would become the Army's new standard infantry rifle, the project was put on hold in April 2005, and was formally canceled on October 31, 2005.
General Dynamics
General Dynamics
General Dynamics Corporation is a U.S. defense conglomerate formed by mergers and divestitures, and as of 2008 it is the fifth largest defense contractor in the world. Its headquarters are in West Falls Church , unincorporated Fairfax County, Virginia, in the Falls Church area.The company has...
was involved in latter stages and H&K had plans to produce the rifle at a plant in Georgia
Georgia (U.S. state)
Georgia is a state located in the southeastern United States. It was established in 1732, the last of the original Thirteen Colonies. The state is named after King George II of Great Britain. Georgia was the fourth state to ratify the United States Constitution, on January 2, 1788...
. H&K was British
Economy of the United Kingdom
The economy of the United Kingdom is the sixth-largest national economy in the world measured by nominal GDP and seventh-largest measured by purchasing power parity , and the third-largest in Europe measured by nominal GDP and second-largest measured by PPP...
-owned at the start of the project, but was later bought back by a group of German
Economy of Germany
Germany is the largest national economy in Europe, the fourth-largest by nominal GDP in the world, and fifth by GDP in 2008. Since the age of industrialisation, the country has been a driver, innovator, and beneficiary of an ever more globalised economy...
investors. Engineering work was done at facilities in the United States and Germany.
History
The U.S. Army's purpose in contracting for this prototype weapon was to provide replacement options for the venerable M16 rifleM16 rifle
The M16 is the United States military designation for the AR-15 rifle adapted for both semi-automatic and full-automatic fire. Colt purchased the rights to the AR-15 from ArmaLite, and currently uses that designation only for semi-automatic versions of the rifle. The M16 fires the 5.56×45mm NATO...
after the XM29 program ran into problems. The Army's goal was a weapon that was cheaper, lighter, and more effective than the M16 and M4 Carbine
M4 carbine
The M4 carbine is a family of firearms tracing its lineage back to earlier carbine versions of the M16, all based on the original AR-15 designed by Eugene Stoner and made by ArmaLite. It is a shorter and lighter variant of the M16A2 assault rifle, with 80% parts commonality.It is a gas-operated,...
series of weapons. The XM8 was not just one weapon, but a system which could be reconfigured with appropriate parts to be any one of several variants from a short-barreled personal defense weapon to a bipod
Bipod
A bipod is a support device that is similar to a tripod or monopod, but with two legs. It provides significant stability along two axes of motion .-Firearms:...
-equipped support weapon. It also included an integrated optical sight and IR laser aiming module/illuminator.
The XM8 was based on the kinetic energy
Kinetic energy
The kinetic energy of an object is the energy which it possesses due to its motion.It is defined as the work needed to accelerate a body of a given mass from rest to its stated velocity. Having gained this energy during its acceleration, the body maintains this kinetic energy unless its speed changes...
module of Alliant Techsystems
Alliant Techsystems
Alliant Techsystems Inc., most commonly known by its ticker symbol, ', is one of the largest aerospace and defense companies in the United States with more than 18,000 employees in 22 states, Puerto Rico and internationally, and 2010 revenues in excess of an estimated...
's XM29 OICW
XM29 OICW
The XM29 OICW was a series of prototypes of a new type of battle rifle that fired 20 mm HE airbursting projectiles. The prototypes were developed as part of the Objective Individual Combat Weapon program in the 1990s...
project, of which the weapon mechanisms were the responsibility of H&K. Following the indefinite delay of the Objective Individual Combat Weapon program
Objective Individual Combat Weapon program
The Objective Individual Combat Weapon or OICW was the next-generation service rifle competition that was under development as part of the United States Army OICW program; the program was eventually discontinued without bringing the weapon out of the prototype phase...
, the U.S. Army requested that the contractors design stand-alone weapons from the XM29's kinetic energy and high explosive modules.
The first 30 XM8 prototypes were delivered by November 2003 for preliminary testing. Later, at least 200 developmental prototypes were procured. Among the complaints during testing was that the battery life was too low for the weapon's powered sight system and some ergonomics issues. Two other key issues were reducing the weapon's weight and increasing the heat resistance of the hand guard, which would start to melt after firing too many rounds. The main testing was largely completed, and the Army pushed for funding for a large field test. However, in 2004 Congress denied $26 million funding for 7,000 rifles to do a wide scale test fielding of the XM8 in 2005. At the time the rifle still had developmental goals that were incomplete, primarily associated with the weapon's weight; the battery life had been extended, and a more heat-resistant plastic hand-guard added. The earliest product brochure lists the target weight for the carbine variant at 5.7 lbs (2.6 kg) with the then current prototype at 6.2 lb (2.8 kg). The weight of the carbine prototype had since grown to 7.5 lbs (3.4 kg) according to a brochure released by HK and General Dynamics
General Dynamics
General Dynamics Corporation is a U.S. defense conglomerate formed by mergers and divestitures, and as of 2008 it is the fifth largest defense contractor in the world. Its headquarters are in West Falls Church , unincorporated Fairfax County, Virginia, in the Falls Church area.The company has...
in January 2005.
Colt Defense
Colt Defense LLC, together with its subsidiaries, is a designer, developer and manufacturer of small arms weapons systems for individual soldiers and law enforcement personnel. It is headquartered in West Hartford, Connecticut...
required the Army to involve Colt in certain small-arms programs. The XM8 program was put on hold by the Army in 2004. The exact reason why this happened is a matter of debate; some combination of the aforementioned technical issues, funding restrictions, and outside pressure being involved.
In 2005, the Army issued a formal Request for Proposals (RFP) for the OICW Increment One family of weapons. This RFP gave manufacturers six months to develop and deliver prototype weapons with requirements very similar to the XM8 capabilities, but with the addition of a squad automatic weapon
Squad automatic weapon
A squad automatic weapon is a weapon used to give infantry squads or sections a portable source of automatic firepower. Weapons used in this role are selective-fire rifles, usually fitted with a bipod and heavier barrel to perform as Light machine guns...
(SAW) configuration. Currently, no XM8 prototypes have been shown that actually match the capabilities of the M249 (e.g. fast barrel replacement, high sustained rate of fire
Rate of fire
Rate of fire is the frequency at which a specific weapon can fire or launch its projectiles. It is usually measured in rounds per minute , or per second .-Overview:...
, belt feed). The OICW Increment One requirement for the SAW includes fast barrel replacement and high sustained rate of fire, but leaves the ammunition feed choice up to the manufacturer.
Funding for the M320 grenade launcher, which is a single-shot under-barrel grenade launcher similar to the M203
M203 grenade launcher
The M203 is a single shot 40 mm grenade launcher designed to attach to a rifle. It uses the same rounds as the older M79 break-action grenade launcher, which utilize the High-Low Propulsion System to keep recoil forces low. Though versatile, and compatible with many rifle models, the M203 was...
that was originally intended for the XM8, was approved. The launcher is actually heavier than the M203, but does offer some advantages. The XM320 was designed for use with the existing inventory of M16s and M4s and is also compatible with the XM8. It can also be used as a stand-alone weapon.
As of July 19, 2005, the OICW Increment One RFP was put on an eight-week hold, with an indication given that the program was being restructured as a joint procurement program including the Army and unnamed other branches. On October 31, 2005, the OICW Increment One RFP was canceled until further notice.
In an article in Jane's Defence Weekly
Jane's Defence Weekly
Jane's Defence Weekly is a weekly magazine reporting on military and corporate affairs, edited by Peter Felstead. It is one of a number of military-related publications named after John F. T. Jane, an Englishman who first published Jane's All the World's Fighting Ships in 1898...
, April 26 2006 (Vol 43, page 30) we learn that "The US Army has again delayed the procurement of its future infantry weapons, this time for more than five years, and is working to field two interim guns in the meantime."
Cancellation
FN SCAR
The Special Operations Forces Combat Assault Rifle, or SCAR, is a modular rifle made by FN Herstal for the United States Special Operations Command to satisfy the requirements of the SCAR competition. This family of rifles consist of two main types...
and HK416. It was later altered and entered as a candidate for the SCAR
FN SCAR
The Special Operations Forces Combat Assault Rifle, or SCAR, is a modular rifle made by FN Herstal for the United States Special Operations Command to satisfy the requirements of the SCAR competition. This family of rifles consist of two main types...
competition but was unsuccessful.
Further testing
In the Fall of 2007 the XM8 was compared to other firearms in a 'dust test.' The competition was based on two previous tests that were conducted in Summer 2006 and Summer 2007 before the latest test in the Fall of 2007. In the Summer 2007 test, M16 rifles and M4 carbines recorded a total of 307 stoppages. In the Fall 2007 test, the XM8 recorded only 127 stoppages in 60,000 total rounds while the M4 carbine had 882. The FN SCARFN SCAR
The Special Operations Forces Combat Assault Rifle, or SCAR, is a modular rifle made by FN Herstal for the United States Special Operations Command to satisfy the requirements of the SCAR competition. This family of rifles consist of two main types...
had 226 stoppages and the HK416 had 233. The difference between the XM8, HK416, and FN SCAR was not statistically significant when correcting for the less reliable STANAG magazine. However, the discrepancy of 575 stoppages between the Summer and Fall 2007 tests of the M4 had Army officials looking into possible causes for the change such as different officials, seasons, and inadequate sample pool size but have stated that the conditions of the test were ostensibly the same. The Army countered the controversy surrounding the M4 by stating, in essence, that troops are generally satisfied with the M4. However respondents indicated in independent interviews quoted in Congress that they would much prefer the M4-derivative HK416 or the XM8 which it builds upon, and that Ranger
United States Army Rangers
United States Army Rangers are elite members of the United States Army. Rangers have served in recognized U.S. Army Ranger units or have graduated from the U.S. Army's Ranger School...
Battalions that were already issued the SCAR liked it better than AR-15-types.
Design
Selective fire
A selective fire firearm has at least one semi–automatic and one automatic mode, which is activated by means of a selector which varies depending on the weapon's design. Some selective fire weapons utilize burst fire mechanisms to limit the maximum or total number of shots fired automatically in...
5.56mm
5.56x45mm NATO
5.56×45mm NATO is a rifle cartridge developed in the United States and originally chambered in the M16 rifle. Under STANAG 4172, it is a standard cartridge for NATO forces as well as many non-NATO countries. It is derived from, but not identical to, the .223 Remington cartridge...
assault rifle
Assault rifle
An assault rifle is a selective fire rifle that uses an intermediate cartridge and a detachable magazine. Assault rifles are the standard infantry weapons in most modern armies...
, firing from a closed rotary bolt. Its design and functioning is similar to that of the Heckler & Koch G36
Heckler & Koch G36
The Heckler & Koch G36 is a 5.56×45mm assault rifle, designed in the early 1990s by Heckler & Koch in Germany as a replacement for the 7.62mm G3 battle rifle. It was accepted into service with the Bundeswehr in 1997, replacing the G3...
assault rifle, of which it is a derivative.
Materials and weight
The materials used to build the XM8 are almost entirely composites — with the notable exception of the cold hammer forged steel barrel. Preliminary tests in desert and Arctic conditions have shown XM8 to be a rugged weapon, though some complaints arose. It is reported to be capable of firing 15,000 rounds without cleaning or lubrication and up to 20,000 rounds before barrel replacement. In contrast, the M16A2 needs to be cleaned often, and has a barrel life of approximately 7,000–8,000 rounds.Much of the expected cost and weight savings are from the weapon's electronic sight. The sight is much more than a 1.5x red dot sight
Red dot sight
A red dot sight is a common classification for a type of non-magnifying reflector sight for firearms that gives the user an aimpoint in the form of an illuminated red dot...
, including IR lasers and pointers as well. The baseline XM8 carbine (with its integrated sight), for example, can be compared to an M4 carbine with a host of previous-generation electronic add-ons like the AN/PEQ-2
AN/PEQ-2
The AN/PEQ-2 Target Pointer/Illuminator/Aiming Light is a laser sight for use on rifles fitted with a Picatinny rail. It is manufactured by Insight Technology.The device is mil-spec and is currently in active service with the US armed forces...
, Aimpoint CompM2
Aimpoint CompM2
The CompM2 is a battery powered non-magnifying red dot type of reflex sight for firearms manufactured by Aimpoint AB. In the U.S. military, it is designated M68 Close Combat Optic and is also known as M68 Aimpoint and is designed to meet United States military standards...
, Advanced Combat Optical Gunsight
Advanced Combat Optical Gunsight
Advanced Combat Optical Gunsights are a series of telescopic sights manufactured by Trijicon. The ACOG is designed to be used on the M16 rifle and M4 carbine, but Trijicon has developed ACOG accessories for certain other firearms...
, and/or BUIS. Without the advantage of the next-generation combined electronics sight, the XM8 would be both heavier and more expensive than the firearms it is intended to replace. The XM320
XM320
M320 Grenade Launcher Module is the U.S. Military's designation for a new single-shot 40 mm grenade launcher system to replace the M203.for the US Army, while other services use older M203...
grenade launcher, intended to be used with the current M4/M16 firearms as well as the XM8 family, includes feature enhancements.
Accessories
XM8 abandons the standard MIL-STD-1913Picatinny rail
The Picatinny rail or MIL-STD-1913 rail or STANAG 2324 rail or a "Tactical Rail" is a bracket used on some firearms in order to provide a standardized mounting platform. A similar system is the Weaver rail mount.-Description:...
, for attachment of weapon accessories, in favor of a new standard referred to as PCAP (Picatinny Combat Attachment Points), small oval holes on the forward grip. (A variant was designed with MIL-STD-1913 rails — XM8 R; and some early XM8 prototypes had rails.) PCAP is not backwards compatible with currently fielded attachments that use MIL-STD-1913 rails without using an adapter. The benefit of PCAP, however, is the precision of the accessory's connection with the body of the weapon; accessories utilizing MIL-STD-1913 rails often need adjustment if they are removed and reattached. Additionally, most standard accessory functionality is built-in to the XM8. Where functionality was missing, it was anticipated that accessories would be redesigned to utilize PCAP. In the new OICW Increment One competition, the Army has left the choice of attachment technology up to the manufacturer, with requirements built into the RFP as to the ability of sights to maintain their zero.
The M4 carbine barrel is 14.5 inches (368 mm) and the XM8 barrel is 12.5 inches (318 mm) but the rifles have the same overall length. Although a shorter barrel generally results in lower muzzle velocity, Polygonal rifling
Polygonal rifling
Polygonal rifling is a type of gun barrel rifling where the traditional lands and grooves are replaced by "hills and valleys" in a rounded polygonal pattern, usually a hexagon or octagon....
partially compensates from the loss of velocity from a shorter barrel. An electronic round counter was proposed for the XM8. The system would have tracked the number of rounds fired and the date and time of each shot. The data would then be accessed wirelessly by a device like a PDA. Another benefit would be to monitor unauthorized weapon use or corroborate field reports. Other features included completely ambidextrous controls and an integrated red dot/3x optical zoom scope (later changed to a red dot/1x sight). However the designated marksman
Designated marksman
The designated marksman is a military marksman role in a U.S. infantry squad. The term sniper was used in Soviet doctrine although the soldiers using the Dragunov were the first to use a specifically designed designated marksman's rifle. Sniper is also used in Russian doctrine...
configuration used a 3.5x magnification scope.
Variants
For much of its life, four different models were proposed: a compact PDW (personal defense weapon) with a 9.5-inch (241 mm) barrel, a carbine with a 12.5-inch (318 mm) barrel, a sniper and automatic rifle variant, both with 20-inch (508 mm) barrels. In addition, accessories such as optical sights, a grenade launcherGrenade launcher
A grenade launcher or grenade discharger is a weapon that launches a grenade with more accuracy, higher velocity, and to greater distances than a soldier could throw it by hand....
, and a bipod
Bipod
A bipod is a support device that is similar to a tripod or monopod, but with two legs. It provides significant stability along two axes of motion .-Firearms:...
were 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 M16, the XM8 was chambered for the standard 5.56 mm NATO
5.56x45mm NATO
5.56×45mm NATO is a rifle cartridge developed in the United States and originally chambered in the M16 rifle. Under STANAG 4172, it is a standard cartridge for NATO forces as well as many non-NATO countries. It is derived from, but not identical to, the .223 Remington cartridge...
round and was normally equipped with a 30-round plastic box magazine
Magazine (firearm)
A magazine is an ammunition storage and feeding device within or attached to a repeating firearm. Magazines may be integral to the firearm or removable . The magazine functions by moving the cartridges stored in the magazine into a position where they may be loaded into the chamber by the action...
. Although, this magazine was not compatible with M4 and M16's metal STANAG magazine
STANAG magazine
A STANAG magazine is a type of detachable firearm magazine proposed by NATO in October 1980. Shortly after NATO's acceptance of the 5.56x45mm NATO rifle cartridge, Draft Standardization Agreement 4179 was proposed in order to allow the military services of member nations easily to share rifle...
. A 100-round dual drum Beta C-Mag
Beta C-Mag
The Beta C-Mag is a 100-round capacity magazine designed by Jim Sullivan and adapted for use in numerous firearms firing the 5.56×45mm NATO, 7.62×51mm NATO, and 9×19mm Parabellum cartridges. C-Mag is short for century magazine, referring to its hundred-round capacity. It has two drum units, each of...
style magazine could also be used.
One of the XM8's unique features was its modularity. In addition to attachments mentioned above, this modularity allowed for quick repairs, barrel length changes, and even caliber changes in the field. Along with its basic components, the XM8 would have complemented the XM29, with such features as identical accessory mounts.
The number and type of variants in the family varied over its lifetime, this overview with three main versions is based from a press release in the early 2000s.
- XM8 Compact Carbine: 9 in (229 mm) barrel, PDW configuration, folding stock or buttcap; muzzle velocityMuzzle velocityMuzzle velocity is the speed a projectile has at the moment it leaves the muzzle of the gun. Muzzle velocities range from approximately to in black powder muskets , to more than in modern rifles with high-performance cartridges such as the .220 Swift and .204 Ruger, all the way to for tank guns...
720 m/s (2,362 ft/s) - XM8 Carbine with XM320 grenade launcher: 12.5 in (318 mm) barrel; muzzle velocity 815 m/s (2,674 ft/s)
- Automatic Rifle / Designated Marksmen: heavy 20 in (508 mm) barrel, integrated folding bipod, 4X sight, 30/100 round magazine; muzzle velocity 916 m/s (3,005 ft/s)s
See also
- XM29 OICWXM29 OICWThe XM29 OICW was a series of prototypes of a new type of battle rifle that fired 20 mm HE airbursting projectiles. The prototypes were developed as part of the Objective Individual Combat Weapon program in the 1990s...
- XM25 Individual Airburst Weapon System
- XM307XM307The XM307 Advanced Crew Served Weapon was a developmental 25 mm belt-fed Grenade Machine Gun with smart shell capability. It is the result of the OCSW or Objective Crew Served Weapon project. It is lightweight and designed to be two-man portable, as well as vehicle mounted...
- XM312XM312The XM312 is a heavy machine gun derived from the XM307 25 mm autocannon and chambered for the .50 BMG cartridge. It was designed in response to a request by the U.S...
- Heckler & Koch G36Heckler & Koch G36The Heckler & Koch G36 is a 5.56×45mm assault rifle, designed in the early 1990s by Heckler & Koch in Germany as a replacement for the 7.62mm G3 battle rifle. It was accepted into service with the Bundeswehr in 1997, replacing the G3...
- Kinetic projectiles
- Kinetic energy penetratorKinetic energy penetratorA kinetic energy penetrator is a type of ammunition which, like a bullet, does not contain explosives and uses kinetic energy to penetrate the target....
- XM320XM320M320 Grenade Launcher Module is the U.S. Military's designation for a new single-shot 40 mm grenade launcher system to replace the M203.for the US Army, while other services use older M203...
- Adaptive Combat RifleAdaptive Combat RifleThe Adaptive Combat Rifle is the production name for an updated version of the Masada Adaptive Combat Weapon System. In late January 2008, Bushmaster entered into a licensing agreement with Magpul whereby Bushmaster would take over production, future development and sales of the Masada...
, modular rifle system. - Beretta ARX 160
- FN SCARFN SCARThe Special Operations Forces Combat Assault Rifle, or SCAR, is a modular rifle made by FN Herstal for the United States Special Operations Command to satisfy the requirements of the SCAR competition. This family of rifles consist of two main types...
- Barrett REC7