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United States Navy Mark 12 Special Purpose Rifle (Mk 12 SPR)

Sniper Rifle / Designated Marksman Rifle (DMR) [ 2002 ]

The Mk 12 SPR has been used with deadly efficiency in both Afghanistan and Iraq theaters of war.

Authored By: Staff Writer | Last Edited: 08/12/2018 | Content ©www.MilitaryFactory.com | The following text is exclusive to this site.

The Mark 12 Special Purpose Rifle (Mk 12 SPR) entered service with the United States Special Forces in 2002 and has seen continuous use since. The weapon has been featured prominently in operations throughout the Afghanistan and Iraq theaters of war, often times in the hands of the highly-trained specialists of the U.S. Army and U.S. Navy. A prime operator of the SPR is, in fact, the U.S. Navy SEALs which dictates that the SPR be a reliable, extremely effective and robust weapon system. The Mk 12 was specifically developed for use by the Naval Surface Warfare Center Crane Division (NSA Crane) and is largely based on workings of the AR-15 / M16 pattern rifle with a few noticeable external additions and modifications.

The Mk 12 was born out of a joint U.S. Army / Navy requirement calling for a compact, semi-automatic sniper system. Multiple prototypes were considered and these were then heavily tested resulting in the finalized "Mk 12" form. As in the AR-15 and M16, the Mk 12 is chambered 5.56x45mm NATO but the cartridges themselves are specially-developed for the Mk 12's semi-automatic, gas-operated rotating bolt action system. The weapon feeds from a 20- or 30-round detachable box magazine and, more or less, retains the AR-15/M16's form and function in-the-field. Effective range is listed out to 600 yards with a muzzle velocity nearing 3,050 feet-per-second. The pistol grip is ergonomically grooved for a firm hand hold while the trigger is set within an integrated guard. The magazine well is located just ahead of the trigger unit in conventional fashion.

The forend is made up of a perforated, tubular handguard to which an accessories rail section is affixed along the forward lower face - this allows use of a collapsible bipod for steady firing. The upper portion of the receiver and the forend also sport a rail system for the use of tactical accessories and optics as needed. The shoulder stock extends from a collapsible tubular frame and helps the operator achieve a stable four-point firing position (both hands, a bipod and the shoulder stock) for maximum accuracy at distance. The barrel protrudes only a short distance from the forend and is capped by a single-baffled muzzle brake. The barrel measures 18 inches in length while overall length of the SPR weapon is 37.5 inches. A fully-loaded rifle weighs 10lb, slightly more than the original M16. In comparison, the M16 measures in at 39.5 inches long with a 20-inch barrel length.

There are several notable iterations of the Mk 12 in circulation: the "Mk 12 Mod 0" is used by Army special forces and "Mk 12 Mod 1" is used by Navy special forces. The formal "long designation" for the rifle is "United States Navy Mark 12 Mod 0/1 Special Purpose Rifle".©MilitaryFactory.com
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Service Year

United States national flag graphic
United States


Sniper Rifle / Designated Marksman Rifle (DMR)

ArmaLite; Colt; Knights Armament Company - USA / Diemaco - Canada
(View other Arms-Related Manufacturers)
National flag of the United States United States
(OPERATORS list includes past, present, and future operators when applicable)
Automatic Function
Features a mechanical function to automate the firing action.
Accuracy / Precision
Long-range accuracy / precision capable; suitable for sniping, particularly when equipped with sighting aids.
Special Forces
Qualities of this weapon have shown its value to Special Forces elements requiring a versatile, reliable solution for the rigors of special assignments.

Overall Length
952 mm
37.48 in
Barrel Length
457 mm
17.99 in
Empty Wgt
9.92 lb
4.50 kg

Adjustable Iron; Optional Optics


Gas-Operated, Rotating Bolt

Rotating Bolt
System utilizes internal mechanism to lock the breech or rear barrel assembly prior to firing.
Gas-operated system is featured, typically involving a gas cylinder and rear-driven piston directing energy to the bolt component.
(Material presented above is for historical and entertainment value and should not be construed as usable for hardware restoration, maintenance, or general operation - always consult official manufacturer sources for such information)


5.56x45mm NATO

Sample Visuals**

Graphical image of a 5.56mm intermediate rifle cartridge
Rounds / Feed

20- or 30-round detachable box magazine
Cartridge relative size chart
*May not represent an exhuastive list; calibers are model-specific dependent, always consult official manufacturer sources.
**Graphics not to actual size; not all cartridges may be represented visually; graphics intended for general reference only.
Max Eff.Range
1,800 ft
(549 m | 600 yd)
Muzzle Velocity
3,050 ft/sec
(930 m/sec)

Mk 12 SPR - Base Series Designation
Mk 12 Mod 0 - Used by the US Army Rangers operatives.
Mk 12 Mod 1 - Used by the US Navy SEALs operatives.

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Images Gallery

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Image of the United States Navy Mark 12 Special Purpose Rifle (Mk 12 SPR)
Left side view of the Mk 12 SPR on display


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