Weapon Name- .300 Magnum Nemo Omen
Round Type- MK 248 MOD 1 .300 Winchester Magnum
Over-all length- 38.5 inches, 35.5 inches collapsed
Barrel length- 18 inches
Weight- 9.5 lb
Rate of Fire- Semi auto
Feed Mechanism- Detachable box magazine
Round Capacity- 14 round magazines
Effective Range- 800 meters
Range- 1500 meters
Accuracy- .5 MOA
Accessories- Picatinny Rails
Quick switch firing mechanism- N/A
Scope/Sights- Picatinny Rails
Muzzle Velocity- 869 m/s, 14.3 grams
Firing System- Direct impingement
Miscellaneous/electronic information- A heavily modified AR-10 firing .300 win mag designed for precision accuracy.
Basic Information
The weapon is a heavily modified AR-10 firing a modified .300 winchester magnum designed specifically for sniper use. With approximately 1 MOA, and delivering over 5,000 joules, the weapon's power and performance in a hand held semi automatic rifle is unmatched. Capable of piercing light ceramic armor, the weapon has an effective range of 1500 yards, and in semi automatic fire is capable of reaching out to a mile. With a muzzle break and suppressor, the weapon has light recoil and noise, and is more easily controllable than a standard 7.62mm without a muzzle break. The weapon comes with a 14 round detachable box magazine, and is over-all based on the AR-10. Using a direct impingement gas system, the weapon is based on the Nemo Omen recon rifle.
The U.S. government purchased MK 248 MOD 1 .300 Winchester Magnum match-grade ammunition in 2009 for use in adapted M24 Sniper Weapon Systems and other .300 Winchester Magnum sniper rifles like the U.S. Navy Mk.13s. This ammunition was developed as a .300 Winchester Magnum Match Product Improvement (PIP) and uses the 220 gr (14.26 g) Sierra MatchKing Hollow Point Boat Tail (HPBT) very-low-drag bullet fired at a nominal muzzle velocity of 2,850 ft/s plus or minus 50 ft/s (869 m/s ± 15.2 m/s). According to the U.S. Navy this ammunition should increase the maximum effective range of .300 Winchester Magnum sniper rifle systems to 1,500 yards (1,370 m), decrease wind deflection on bullets in flight and use Hogdon H1000, a reduced muzzle flash propellant that remains temperature stable across an operational temperature range of −25 °F to +165 °F (−32 °C to 74 °C).
Several companies, among them HS precision, Kimber and Remington manufacture rifles chambered for the .300 Winchester Magnum specifically targeted at law enforcement agencies. The Chattanooga Police Department and Minot Police Department S.W.A.T units and the L.A. County Sheriffs Department's Special Enforcement Bureau which have adopted the .300 Winchester Magnum in some capacity. Due to the power and performance of the .300 Winchester Magnum cartridge the cartridge is more likely to be employed by specialist units within a police department rather than as a general service weapon issued to law enforcement agents
