Mk 12 Special Purpose Rifle

United States Navy MK 12 SPR (Special Purpose Rifle)
An SPR
Type	Designated marksman rifle
Place of origin	United States
Service history
In service	2002–2017
Wars	Operation Enduring Freedom Operation Iraqi Freedom
Production history
Designer	Naval Surface Warfare Center Crane Division
Variants	SPR, SPR/A, SPR/B MK 12 MOD 0 MK 12 MOD 1 MK 12 MOD H
Specifications
Mass	10 lb (4.5 kg) (fully loaded, heavy barrel and optic mounted)
Length	37.5 inches (952.5 mm)
Barrel length	MOD 0/1 variant: 18 in (457.2 mm) MOD H variant: 16 in (406.4 mm)
Cartridge	5.56×45mm Mk 262
Action	Gas-operated, direct impingement, rotating bolt
Muzzle velocity	2,750 ± 20 ft/s (838.2 ± 6.1 m/s) using Mk 262 Mod 1 ammunition
Effective firing range	700 m (770 yd)
Feed system	20- or 30-round STANAG magazine[1]

The United States Navy Mk 12 MOD 0/1/H Special Purpose Rifle (SPR) is a designated marksman rifle that was in service with United States Special Operations Forces in the designated marksman role until 2017, also designed to be shorter than standard weapons.^[2][3] SPR initially stood for Special Purpose Receiver as it referred to an add-on upper receiver assembly (part of the proposed SOPMOD upgrades),^[4][5] but that nomenclature changed to Special Purpose Rifle as the weapon became a stand-alone weapons system.^[6]

The SPR was eventually type-classified by the U.S. Navy as the Mk 12.^[6] The weapon was developed by the Naval Surface Warfare Center Crane Division for US military special operations units.^[6]

The rifle is designed to fire semi-automatically, although it has the option to fire in full auto in case of emergencies.^[7]