6.8mm Remington SPC

6.8×43mm Remington SPC

6.8 SPC (left), .223 Remington (right)

Production history

Designer

Remington Arms, USSOCOM

Designed

2002–2004

Specifications

Parent case

.30 Remington

Case type

Rimless, bottlenecked

Bullet diameter

0.277 in (7.0 mm)

Neck diameter

0.298 in (7.6 mm)

Shoulder diameter

0.402 in (10.2 mm)

Base diameter

0.421 in (10.7 mm)

Rim diameter

0.422 in (10.7 mm)

Rim thickness

0.049 in (1.2 mm)

Case length

1.667 in (42.3 mm)

Overall length

2.260 in (57.4 mm)

Case capacity

34.8-36.9 gr H2O

Maximum pressure (C.I.P)

42,000 psi (290 MPa)

Maximum pressure (SAAMI)

54,000 psi (370 MPa)

Ballistic performance

Bullet mass/type	Velocity	Energy
7.45 g (115 gr) fmj	2,575 ft/s (785 m/s)	1,694 ft·lbf (2,297 J)
7.78 g (120 gr) sst	2,460 ft/s (750 m/s)	1,612 ft·lbf (2,186 J)
7.1 g (110 gr) Sierra Pro Hunter	2,500 ft/s (760 m/s)	1,525 ft·lbf (2,068 J)
5.5 g (85 gr) Barnes TSX with "tactical" factory SSA load	3,070 ft/s (940 m/s)	1,780 ft·lbf (2,410 J)

Test barrel length: 410 millimetres (16 in)

The 6.8 mm Remington Special Purpose Cartridge (aka 6.8 SPC, 6.8 SPC II & 6.8×43mm) is a rifle cartridge that was developed by Remington Arms in collaboration with members of the U.S. Army Marksmanship Unit, United States Special Operations Command to possibly replace the 5.56 NATO cartridge in a Short Barreled Rifle(SBR)/Carbine.

Based upon the .30 Remington cartridge, it is midway between the 5.56×45mm NATO and 7.62×51mm NATO in bore diameter and muzzle energy. It uses the same diameter bullet (not usually the same weight) as the venerable .270 Winchester hunting cartridge.

The 6.8mm SPC cartridge was designed to address the deficiencies of the terminal performance of the 5.56×45mm NATO cartridge currently in service with the U.S. Armed Forces. The cartridge was the result of the Enhanced Rifle Cartridge program. The 6.8 SPC (6.8×43mm) was initially developed by MSG Steve Holland and Chris Murray, a United States Army Marksmanship Unit gunsmith, to offer superior downrange lethality over the 5.56 NATO/.223 Remington in an M16 pattern service rifle with minimal loss of magazine capacity and a negligible increase in recoil. The goal was to create a cartridge that would bridge the gap between 5.56 mm and 7.62×51mm NATO.

The program started the design by using a .30 Remington case, which was modified in length to fit into magazines that would be accommodated by the magazine wells of the M16 family of rifles and carbines that are currently in service with the U.S. Armed Forces.

In tests, it was determined that a 6.5 mm caliber projectile had the best accuracy and penetration, with historical data going back for decades of US Army exterior and terminal ballistic testing, but a 7 mm projectile had the best terminal performance. Further tests showed that a 6.8 mm caliber projectile was a compromise between the two, providing accuracy, reliability and terminal performance up to 500 meters. The combination of the cartridge case, powder load, and projectile easily outperformed the 7.62×39mm Soviet cartridge, with the new cartridge proving to be about 61 m/s (200 ft/s) faster. The resulting cartridge was named the 6.8 Remington Special Purpose Cartridge due to the size of its projectiles and the fact that it was based on the .30 Remington case.

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Wikipedia