6.8 mm Remington SPC

Infobox Firearm Cartridge
name=6.8x43mm Remington SPC


caption=6.8 mm Remington SPC (Left) as compared to the 5.56x45mm NATO cartridge (Right)
origin=flagcountry|United States
type=Rifle
designer=Remington, SOCOM
design_date=2002-2004
parent=.30 Remington
case_type=Rimless, bottlenecked
bullet=0.277
neck=0.298
shoulder=0.402
base= 0.421
rim_dia=0.422
rim_thick=0.049
case_length= 1.676
length=2.315
rifling=
primer=
velocity=
energy=
bw1=115
btype1=(7.45g)
vel1=2625
en1=1759
test_barrel_length= 24 in (609.6 mm)
balsrc= Remington [ [http://www.remington.com/products/ammunition/ballistics/comparative_ballistics_results.aspx?data=R68R1*R68R2*RM68R1*PRC68R4 Remington Web Page: 6.8 SPC Velocity/Ballistics] ]

The 6.8 mm Remington SPC (or 6.8x43mm) is a new rifle cartridge that was developed with collaboration from individual members of US SOCOM. [ [http://www.defensereview.com/modules.php?name=News&file=article&sid=383 Not a private endeavor or fully sanctioned government project] ] Based upon the .30 Remington cartridge [ [http://www.chuckhawks.com/30_Rem.htm 30 Rem ] ] , it is midway between the 5.56x45mm NATO and 7.62x39mm in bore diameter and velocity with more energy than both. It is particularly adaptable to current 5.56 mm NATO firearms, the cartridge overall length being comparable.

Though ballistically similar to the 1950s-era .280 British, improved propellant powders allow the 6.8 mm to have a smaller case. The 6.8 mm SPC (Special Purpose Cartridge) has a muzzle velocity in the 2,400 feet per second (730 m/s) range from a 16 inch (406 mm) barrel using a 115-grain bullet.

Performance

The 6.8 mm Remington SPC is designed to deliver 44% greater energy than the 5.56 mm NATO at 100-200 meters. [ [http://www.65grendel.com/graphics/grendelballistics.pdf 6.8 SPC Velocity/Ballistics - hot loadings] ] When compared to the more powerful and well-established 7.62x51mm NATO cartridge, the 6.8 mm falls short in all of these areas, but has less recoil and is more controllable. While the 6.8 mm generates around 1,759 ft·lbf (2385 J) of muzzle energy with its 115 grain bullet (note: this figure is from a 24" bolt-action test barrel, not the 14.5 inch barrel of the M4 Carbine), the 7.62 mm NATO (M80) fires a 147 grain bullet at 2,750 ft/s for 2460 ft·lbf of energy (838.2 m/s for 3335 J).

While the round is generally intended for use at shorter ranges, this handicap somewhat dampened the initial enthusiasm over the SPC round, and gave competitors like the 6.5 Grendel or improved 5.56 mm rounds an opportunity to compete for acceptance. Many criticisms fall short, however, considering the majority of military engagements (even with modern optics) occur inside 300 m.

The first major manufacturer to offer a 6.8 mm Remington SPC chambered version of the AR-15 was Barrett Firearms Company, offering the Barrett M468. By 2007, most major manufacturers of AR-15 type rifles for the civilian gun market, such as Bushmaster Firearms International, DPMS Panther Arms and Rock River Arms were also producing 6.8 mm Rem SPC carbines. Ruger Firearms produces a 6.8 mm version of their popular Ruger Mini-14 series carbine [ [http://www.ruger-firearms.com/Firearms/FAProdView?model=5814&return=Y Information on the 6.8 SPC Mini] ] . Remington also makes a bolt-action long rifle, 24" barrel Model 700 chambered in the 6.8SPC cartridge.

=Muzzle velocity from a convert|24|in|mm|sing=on barrel=

* 7.45 g (115 gr) Full Metal Jacket (FMJ): 2,625 ft/s (800.1 m/s)
* 7.45 g (115 gr) Boat Tail Hollow Point (BTHP): 2,624 ft/s (799.8 m/s)
* 7.45 g (115 gr) Sierra Match King (SMK): 2,625 ft/s (800.1 m/s)

ee also

* List of firearms
* List of rifle cartridges
* List of individual weapons of the U.S. Armed Forces
* 7 mm caliber Other cartridges of similar size

Notes

External links

* [http://demigodllc.com/~zak/archive/sgn_68spc.pdf Definitive history of 6.8 SPC- "The 6.8 SPC, Is it all that?"]
* [http://www.demigod.org/~zak/firearms/6.8SPC/faq.php 6.8 SPC FAQ]
* [http://www.remington.com/products/ammunition/ballistics/comparative_ballistics_results.aspx?data=R68R1*R68R2*RM68R1*PRC68R4 Remington Ammunition Information]
* [http://www.barrettrifles.com/rifle_468.aspx M468 Rifle]
* [http://www.defensereview.com/modules.php?name=News&file=article&sid=383 Defense Review]
* [http://www.gunblast.com/Barrett-M468.htm Gunblast.com article]
* [http://www.military.com/soldiertech/0,14632,Soldiertech_Ammunition,,00.html Sharper Shooting: Upgrading Ammunition Lethality]