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MK11 / SR 25 Sniper Rifle
XM110 7.62mm Semi-Automatic Sniper System (SASS)

The XM110 7.62 x 51mm Semi-Automatic Sniper System (SASS) is effective against personnel and light materiel targets. The SASS is intended to replace the Army's aging M24 Sniper Weapon System (SWS) with a semi-auto with 5, 10, & 20-round magazines. It supplements the sniper's role to support combat operations with greater firepower and greater possible standoff ranges to improve sniper survivability. The intent was to procure the SASS as a Non-Developmental Item (NDI).

The US Army ARDEC, Picatinny Arsenal, NJ 07806 had a requirement for a 7.62mm semi-automatic sniper system (SASS) capable of delivering precision fire primarily on anti-personnel targets out to a range of 1,000 meters. This system must be a man portable, shoulder fired system utilizing military standard 7.62 x 51 mm caliber ammunition but optimized for the open-tip M118LR long range ammunition. Additionally, M993 Armor Piercing (AP) ammunition will be fired based on specific mission requirements. Compatibility with the existing family of military 7.62 x 51mm caliber ammunition is also required. The SASS shall be capable of safely firing all current U. S. standard 7.62x51mm ammunition and the weapon shall be optimized to fire the M118LR cartridge. Additionally, dual-purpose, anti-personnel/armor piercing ammunition shall have the level of accuracy compatible with SASS (desired) target and range requirements.

The primary components of the system include a rifle, detachable bipod, hard transport/storage case(s), soft carrying case(s), cleaning/maintenance equipment, and manuals. The weapon will have a flash/sound suppressor, high capacity (up to 20-round) detachable box magazines; rails/mounting surfaces for mounting fire control (optics, backup iron sights and aim- light) systems; variable power optics/electro-optics (in order to engage targets between 50 and 1000 meters); and an accompanying spotting scope with range estimation reticle(s) and a night vision interface.

After the rifle is zeroed, the accuracy of the rifle shall be equal to or greater than the M24 SWS. Accuracy shall be measured in minutes of angle. The dispersion of the zeroed rifle, when shoulder fired, shall be equal to or better than the dispersion of the M24 SWS. Dispersion shall be calculated as Average Mean Radius (AMR) as measured at 600 meters. Dispersion characteristics for each lot of ammunition will be provided prior to the start of testing. All targets shall be fired on using M118LR Ammunition or equivalent using five (5) round groups.

The radial distance from the calculated center of impact of the first target compared to the calculated center of impacts of subsequent targets shall be less than or equal to 1.0 Minutes of Angle (MOA). After the rifle is zeroed on the target with the rifle day optic scope, there shall be a minimum of 15 MOA of windage adjustment (in both the left and right directions) and sufficient elevation adjustment to engage targets at 800 meters (1000 meters desired).

The SASS (rifle plus day optic sight (DOS)) requires a 90% probability (98% probability desired) of firing 300 rounds (3 basic loads) without incurring a critical failure (non-operator correctable Essential Function Failures (EFFs)) as defined in the SASS Reliability Failure Definition and Scoring Criteria (FDSC). Combat operations require a 90% probability (98% probability desired) of firing 100 rounds (1 basic load) without incurring an EFF (operator correctable and non-operator correctable) as defined in the SASS Reliability FDSC.

The rifle shall have a detachable bipod. The bipod shall have legs that are independently adjustable in length, and must provide rigid support when firing from the prone position. (It is desired that the bipod allow the weapon to pivot sideways to accommodate firing on sloped surfaces up to 30.) The legs must fold, allowing the weapon to be stored without removing the bipod. The bipod shall attach to the rifle without the use of special tools (preferably without any tools).

There will be a Base contract of thirty (30) systems for Type Classification with four Options. The Option ranges shall be as follows: Option I quantity range of 1-250 each; Option II quantity range of 1 -550 each; Option III quantity ranges of 1-400, 401-800, 801-1,200 each; Option IV quantity ranges of 1-400, 401-800, 801-1,200 each.

The offeror shall submit five (5) bid samples at no cost or obligation to the Government. The winning offeror must be able to deliver operator and maintenance manuals 15 days after contract award. The first fifteen (15) of the thirty (30) SASSs will be delivered with spare parts 30-days after contract award. The remaining fifteen (15) SASSs with spare parts will be delivered 90-days after contract award. The number of spares must be sufficient to cover Pre-Production Qualification Testing (PPQT) and Initial Operational Testing (IOT). There shall also be a First Article Test (FAT) quantity of five (5) items that must be passed prior to approval of Options. In addition, the contractor must be able to sustain a delivery schedule of 100 systems per month beginning 30 days from successful completion of First Article Testing. A competitive Request for Proposal (RFP) [W15QKN-05-R-0433] was posted on the TACOM-ARDEC Acquisition Center website located at: http://procnet.pica.army.mil on or about 30 November 2004.

On 28 September 2005 Knight's Armament Co. (KAC) won the XM110 SASS contract. They did it with a variant of the KAC MK11 MOD 0/SR-25 7.62mm sniper rifle designated as "SR-XM110". The competition had come down to two finalists: the KAC SR-XM110 and the Remington MPD (Military Products Division)/DPMS Panther Arms. The AR-10(T) , which carries a 20-inch, medium-weight target barrel, was ArmaLite's Semi-Automatic Sniper System (SASS) candidate in the Army's XM110 sniper rifle competition. The KAC MK11 MOD0 Navy package is the now famous SR25 specially manufactured by Knight's Armamnet for the Navy Seals.

The Free Floating Rail Adapter System [FF RAS] is used on the SR-25 Match Rifles as well as special forces sniper rifles around the world, including the SR-25 Mk 11 Mod 0. These units use MIL-STD-1913 and MIL-STD-1913 Update Notice 1 "Picattinny" rails incorporated into innovative forend rail assemblies to replace the factory handguards. This improved rail adapter system enables firearms, including M16 type rifles and carbines, without any changes to the weapon except the handguard, to support accessory devices effectively even under combat conditions are provided via the invention by modification of the top semicylinderical part of the rifle's handguard attachment to include an elongated leaf spring arrangement in the front end and a unique rear clamp arrangement at the back end thereof so the leaf spring and rear clamp combination operate to compensate for thermal dimensional changes and combat abuse problems to maintain proper alignment of accessory devices attached to the weapon.

Rapid fire firearms utilized particularly in military operations, e.g., M16 type rifles, are characterized by the heating of the barrels to relatively high temperatures. At such temperatures, the barrels cannot be safely held by the person firing them. Consequently, a variety of handguards have been developed for such rapid fire guns to provide adequate cooling for the gun barrel and mitigate the possibility of burning the hand of the person firing the gun.

With the continuing application of newly developed technologies, e.g., lasers, infrared ray scopes, microcomputerization, etc., to modern warfare, the basic combat weapon, i.e., rifles, carbines and shotguns, have become relatively complicated pieces of hardware. This has resulted in requirements for the association of these weapons with a variety of accessories such as infrared and night vision scopes, laser spotters and the like. Meeting this requirement has resulted in development of various types of multi-purpose rifle mounting devices.

Because of the tremendous abuse to which firearms are continually subjected, particularly in combat, plus the need for as much simplicity as possible in construction and use of the weapon, very serious requirements and restrictions are encountered in the development of militarily acceptable systems for mounting accessories to firearms.


  • Rapid fire/rapid reload, suppressed sniper rifle
  • Exceeds rate-of-fire and lethality of M24 SWS
  • Reduced weight
  • Primarily anti-personnel at ranges equal to or greater than M24
  • Includes enhanced sniper spotting scope system
  • Folding detachable bipod
  • 5-,10-, and 20-round capacity detachable magazines
  • Barrel life greater than 5,000 rounds
  • Variable power day optic scope
  • Detachable weapon suppressor
  • Hard transportation/storage case
  • Integrated Mil-STD 1913 Rail
  • Deployment and cleaning kits

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Page last modified: 07-07-2011 02:47:33 ZULU