6.8 mm Remington SPC

• Name — 6.8×43mm Remington SPC • Designer — Remington Arms, USSOCOM • Design Date — 2002–2004 • Origin — United States • Parent —.30 Remington • Case Type — Rimless, bottlenecked • Bullet — 0.277 • Land — 0.270 in • Neck — 0.306 • Shoulder — 0.402 • Base — 0.422 in • Rim Dia — 0.422 • Rim Thick — 0.049 • Case Length — 1.687 in • Length — 2.260 in • Case Capacity — 34.8-36.9 • Primer — Large Rifle • Max Pressure — 58700 • Pressure Method — C.I.P • Max Pressure2 — 55000 • Pressure Method2 — SAAMI • Bw1 — 7.45 g (115 gr) • Btype1 — Full Metal Jacket • Vel1 — 2575 • En1 — 1694 • Bw2 — 7.78 g (120 gr) • Btype2 — SST • Vel2 — 2460 • En2 — 1612 • Bw3 — 7.1 g (110 gr) • Btype3 — Sierra Pro Hunter • Vel3 — 2500 • En3 — 1525 • Test Barrel Length — 16 in • Vel4 — 3070 • En4 — 1780 • Bw4 — 5.5 g (85 gr) • Btype4 — Barnes TSX with "tactical" factory SSA load

The 6.8 SPC was designed to address the deficiencies of the terminal ballistics of the 5.56×45mm NATO cartridge currently in service with the armed forces of all NATO-aligned countries. The cartridge was the result of the Enhanced Rifle Cartridge Program. The 6.8 SPC (6.8×43mm) was initially developed by Master Sergeant 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 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 comparing various caliber bullets using a.30 Remington parent case, Holland and Murray 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. The combination of the cartridge case, powder load, and projectile easily outperformed the 7.62×39mm and 5.45×39mm Soviet cartridges, with the new cartridge's muzzle velocity proving to be about 200 ft/s faster than the 7.62x39. The 6.8mm Remington SPC was designed to perform better in short-barreled CQB rifles after diminished performance from the 5.56 NATO when the M16A4 was changed from the rifle configuration to the current M4 carbine. The 6.8 SPC delivers 44% more energy than the 5.56mm NATO (M4 configuration) at 100 -. The 6.8mm SPC is not the ballistic equal of the 7.62×51mm NATO cartridge, but it has less recoil, has been said to be more controllable in rapid fire, and is lighter, allowing operators to carry more ammunition than would otherwise be possible with the larger caliber round. The 6.8 mm generates around 1759 ftlbf of muzzle energy with a 115 gr bullet. In comparison, the 5.56×45mm round (which the 6.8 is designed to replace) generates around 1325 ftlbf with a 62 gr bullet, giving the 6.8 mm a terminal ballistic advantage over the 5.56 mm of 434 ftlbf. One of the enigmatic features of this cartridge is its being designed for a shorter-barrel carbine-length rifle than the standard rifle length is (usually 16 in). The round only gains about 25 - for every 25 mm of barrel length past the standard 16 in barrel (all else being equal) up to barrel lengths around 22 - with no gain or loss in accuracy. It also does well in rifles with less than 16 in barrels. In recent developments (the period 2008–2012) the performance of the 6.8 SPC has been increased by approximately 200 to by the work of ammunition manufacturer Silver State Armory LLC (SSA) and a few custom rifle builders using and designing the correct chamber and barrel specifications. The 6.8mm Remington SPC cartridge weighs, depending on the manufacturer and load, between 16.8 and. Also, more recently, LWRC, Magpul and Alliant Techsystems (ATK) introduced a new AR-15 designed for the 6.8 SPC which allows for a proprietary 6.8 Magpul P-mags and an overall cartridge length of 2.32 in. The personal defense weapon (PDW) known as the "Six8" is an SPC II with 1:10 in twist and is able to use all current 6.8 SPC factory ammunition.

• 110 gr Nosler Accubond — 2840 ft/s – Silver State Armory (SSA) • 115 gr OTM — 2800 ft/s – Remington Premier Match • 85 gr Nosler E-Tip — 3100 ft/s – SSA • 90 gr Nosler BSB — 2980 ft/s – SSA • 110 gr Hornady BTHP TAP — 2700 ft/s – Hornady Law Enforcement "tactical" factory load • 115 gr OTM (FMJ) — 2725 ft/s – SSA • 115 gr Boat tail hollow point (BTHP) — 2800 ft/s • 115 gr Sierra Match King (SMK) — 2800 ft/s • 110 gr Hornady V-MAX — 2800 ft/s • 110 gr SCHP — 2800 ft/s – SSA "combat" factory load • 110 gr BTHP OTM & Barnes TSX — 2750 ft/s – Wilson "combat" factory load • 85 gr Barnes TSX — 3180 ft/s – SSA "tactical" factory load • 90 gr Speer Gold Dot — 3050 ft/s – Federal(ATK) "tac/mil" load

• 110 gr Nosler Accubond — 2800 ft/s- Silver State Armory (SSA) • 115 gr OTM — 2700 ft/s- Remington Premier Match • 95 gr Barnes TTSX — 2880 ft/s – Doubletap • 90 gr Bonded Defense JSP — 2980 ft/s – Doubletap • 100 gr Nosler Accubond — 2805 ft/s – Doubletap • 110 gr Nosler Accubond — 2710 ft/s – Doubletap • 115 gr Full metal jacket boat tail — 2645 ft/s – Doubletap • 90 gr Speer TNT — 2980 ft/s- SSA

• 110 gr Nosler Accubond — 2700 ft/s- Silver State Armory (SSA) • 115 gr OTM — 2625 ft/s- Remington Premier Match • 85 gr Barnes TSX — 3030 ft/s – SSA • 85 gr Nosler E-Tip — 2950 ft/s – SSA • 90 gr Nosler BSB — 2840 ft/s – SSA • 110 gr Hornady V-MAX — 2650 ft/s • 115 gr Sierra Match King (SMK) — 2650 ft/s • 115 gr OTM (FMJ) — 2575 ft/s – SSA • 85 gr Barnes TSX — 3070 ft/s – SSA "tactical" factory load • 90 gr Speer Gold Dot — 2900 ft/s- Federal(ATK) "tac/mil" load • 95 gr Barnes TTSX — 2600 ft/s – Wilson Combat factory load • 110 gr SCHP — 2650 ft/s – SSA "combat" factory load • 110 gr Hornady BTHP TAP — 2550 ft/s – Hornady Law Enforcement "tactical" factory load • 110 gr BTHP OTM & Barnes TSX — 2600 ft/s – Wilson "combat" factory load • 140 gr Berger VLD — 2401 ft/s – SSA factory load. (Discontinued)

• Cartridge — Muzzle velocity — 200 yd drop — 200 yd velocity — 400 yd drop — 400 yd velocity • 5.56×45mm 55 gr M193 — 3073 ft/s — 2.2 in — 2353 ft/s — 27.8 in — 1743 ft/s • 5.56×45mm 77 gr OTM — 2679 ft/s — 3.3 in — 2216 ft/s — 32.7 in — 1810 ft/s • 6.8×43mm SPC 115 gr SMK — 2650 ft/s — 3.5 in — 2143 ft/s — 35.4 in — 1677 ft/s • 6.8×43mm SPC 110 gr V-MAX — 2650 ft/s — 3.3 in — 2208 ft/s — 31.1 in — 1811 ft/s • 7.62×39mm — 2300 ft/s — 3.3 in — 1787 ft/s — 53.8 in — 1324 ft/s • 7.62×51mm 168 gr SMK — 2600 ft/s — 3.4 in — 2235 ft/s — 32.3 in — 1891 ft/s Typical trajectory information from carbines with drop and velocity calculated at sea level with a 100 yd zero.

By late 2004 the 6.8×43mm SPC was said to be performing well in the field against enemy combatants in special operations. However the cartridge was not used by conventional US military personnel. It was not adopted for widespread use due to resistance from officials. The 6.8 SPC was designed for better terminal effectiveness at the shorter ranges of urban combat experienced in Iraq. When fighting in Afghanistan began to intensify, engagements began taking place at greater distances, where the 6.8 SPC begins to falter. Experiments suggested that the comparatively short 6.8 mm bullets became ineffective at longer ranges. In 2007, both the U.S. SOCOM and the U.S. Marine Corps decided not to field weapons chambered in 6.8 mm due to logistical and cost issues. While there are many rumors of evaluations of the cartridge by several major federal and local law enforcement agencies, the US Drug Enforcement Administration has allowed individual agents to purchase the M6A2 D-DEA – which uses the 6.8mm Remington SPC – as an authorized alternative to their duty weapon. In 2010 the Jordanian state-owned arms manufacturer KADDB announced that they would be producing 6.8 mm rifles and carbines for the Jordanian Army. There is also a contract between LWRC, Magpul, Alliant Techsystems and the Saudi Royal Guard for around 36,000 Six8 PDWs and an undisclosed amount of ATK/Federal XD68GD (90gr Gold Dot "training" ammo) and proprietary Magpul 6.8 Pmags specifically for the LWRC Six8.

The first major manufacturer to offer a 6.8mm Remington SPC-chambered version of the AR-15 was Barrett Firearms Company, offering the Barrett M468 and later the REC7. By 2007, most major manufacturers of AR-15-type rifles for the civilian gun market were offering rifles in this caliber. Dedicated AR upper receiver assemblies chambered for the round are produced by a number of smaller firms, including Daniel Defense. Ruger Firearms no longer produces a 6.8 mm for their Ruger SR-556 piston-driven AR-15 variant. The Stag Arms hunter and tactical models utilize the newer chamber (SPC II) and specified twist rates to accommodate higher pressure loadings, as well as upper receivers in left-handed configurations. Rock River Arms has an LAR-6.8 X Series rifle and uppers. Microtech Small Arms Research offers their version of the Steyr AUG in 6.8. Robinson Armament Co. offers the XCR-L in 6.8, which can be easily converted between 6.8, 5.56, and 7.62×39. Bushmaster delivered a 6.8 SPC II conversion kit to the market as of October 2018. Ruger Firearms chambered their Mini-14 ranch rifle in this round for several years; however, it has been discontinued.