6.8x43mm SPC (Special Purpose Cartridge)
The existing standard cartridge or chambering for the military's M16 rifle is the .223 Remington or 5.56 mm NATO (military designation) cartridge. It fires a .224 caliber bullet weighing 62 grains in the military issue M855 ammunition. Bullets weighing as much as 77 grains are currently in use by the US military to increase the performance of the 5.56 mm NATO cartridge and have increased the terminal performance of the cartridge, but its terminal effects are still less than desirable for what is considered an adequate combat cartridge. The shortcomings in the performance of the 5.56 mm NATO cartridge are well documented in current and past military conflicts, and the cartridge's ineffectiveness is more pronounced when the enemy combatants are under the influence of drugs that affect the central nervous system.
An alternative for heavier machine guns is the .308 or 7.62 mm caliber bullet. The most common military caliber utilizing the .308 or 7.62 mm caliber bullet is the 308 Winchester or 7.62 mm NATO cartridge. The performance of the 7.62 NATO is also well documented in combat and is known for its increased stopping power. The U.S. M14 rifle fires the 7.62 mm NATO cartridge as does the U.S. M240 machinegun, as well as several aircraft mounted machineguns and the mini-gun. The AK47 also utilizes a 7.62 mm bullet.
What is needed is a cartridge that will provide improved stopping power without over penetrating, and is compatible with the standard size M16/AR15 rifle platform.
The 6.8x43mm SPC (Special Purpose Cartridge) was conceived by a US Army 5th Special Forces Group soldier in a quest to improve the terminal ballistics of the M4 Carbine. The U.S. Army Marksmanship Unit and others assisted the Spec Ops team heading the project. Although the main objective was increased lethality, the new cartridge would go far beyond that in terms of accuracy and performance.
The 6.8mm [.270 military cartridge] Remington SPC cartridge was developed to provide increased lethality and better long range capability than current 5.56mm NATO or 7.62x39 through higher energies. The shell body diameter is larger than 5.56mm NATO but smaller than 7.62x39. The cartridge length is the same as 5.56mm NATO. The modular approach of M16 weapons family allows use of 6.8mm Rem SPC cartridge with dedicated upper receiver and magazine.
The 6.8mm Remington SPC is available with 115 gr Hornady Open-tipped match (OTM), 115 gr Sierra HPBT Match and 115 gr FMJ. Muzzle velocity is 2800 ft/s from a 24" barrel, 2625 ft/s from 16" barrel and 2475 ft/s from a 12" barrel, with 1 MOA dispersion typical. The chamber pressure is 55,000 psi MAP via conformal transducer. 28 rds of 6.8mm Rem SPC - 115 gr OTM weighs ~1.06 lbm, 30 rds 5.56mm NATO - 62 gr FMJ weighs ~0.76 lbm, 20 rds 7.62mm NATO - 150 gr FMJ weighs ~1.07 lbm.
Remington 6.8mm SPC can be used with existing M16/M4 lowers with dedicated upper receiver and magazines. The 6.8mm Rem SPC offers higher energy for improved down range performance versus 5.56mm NATO and 7.62x39. Terminal performance in gelatin has been illustrated at 25 feet with short barreled weapons and at 50 yds with intermediate length barreled weapons. The 115 gr Hornady OTM provides for greater and more immediate temporary expansion cavity. The 6.8mm Rem SPC has been submitted to SAAMI.
By late 2004 the 6.8x43mm SPC was said to be performing well in the field against enemy combatants. Special Operations end users were reported to be very pleased with it.
Dr. Martin Fackler’s research at the Letterman Army Institute of Research Wound Ballistic Laboratory during the 1980s illuminated the yaw and fragmentation mechanism by which 5.56x45mm FMJ bullets create wounds in tissue. “If 5.56mm bullets fail to upset (yaw, fragment, or deform) within tissue, the results are relatively insignificant wounds, similar to those produced by .22 long rifle bullets – this is true for all 5.56x45mm bullets, including both military FMJ and OTM (open tip match) and civilian JHP/JSP designs used in law enforcement. As expected, with decreased wounding effects, rapid incapacitation is unlikely: enemy soldiers may continue to pose a threat to friendly forces and violent suspects can remain a danger to law enforcement personnel and the public. This failure of 5.56x45mm bullets to yaw and fragment can be caused by reduced impact velocities as when fired from short-barreled weapons or when the range to the target increases...."
The article “Do we need a new service rifle cartridge” by Jim Schatz demonstrated the ineffectiveness and lack of lethality of the 5.56mm cartridge. For example, during a Special Forces mission in Afghanistan, an insurgent was shot 7–8 times before falling to the ground. That same insurgent then somehow regained consciousness to reengage the Special Forces soldier. Schatz noted "The unique physical stature (narrow torso) of many of the malnourished Middle Eastern combatants when struck by the M855 projectile often produces insignificant wounds similar to those produced by .22 Long Rifle ammunition. Unless the M855 projectile yaws in the target, through and through shots is the norm..."
In November 2012, Program Executive Office (PEO) Soldier, the materiel developer for virtually all individual equipment Soldiers use in combat, presented its 30-Year Modernization Strategy to Army Acquisition Executive (AAE) the Hon. Heidi Shyu. The modernization planning process begins with concepts, provided by the U.S. Army Training and Doctrine Command's (TRADOC's) Army Capabilities Integration Center (ARCIC) and U.S. Army Maneuver Center of Excellence (MCoE), which drive threat-informed capabilities-based assessments (CBAs) resulting in a prioritized list of gaps.
Army discussion centered on the need for a small arms ammunition configuration study, in line with the HQDA G-3 directive of Dec. 5, 2013. The purpose of the study is "to provide an updated ammunition solution assessment to mitigate the capability gaps prescribed in the Small Arms CBA, and inform small arms weapons priorities and modernization strategy."
The Army undertook its Small Arms Ammunition Configuration study to identify the optimal caliber for small arms capabilities. The study was an acknowledgement that there is more to combat effectiveness than just the weapon. The combat effectiveness "formula" is Combat Effect = Soldier + Weapon + Enablers + Ammunition + Training or SWEAT. The SAAC study would inform future small arms requirements and determine the caliber potential in conjunction with associated weapon and fire control technology. The study was also in synch with the Army's new approach to the material aspects of SWEAT, which is now focused on first achieving enhanced, consistent terminal effects on a particular target set through the right ammunition before considering other aspects of the weapon system that could be upgraded for increased lethality. Numerous other efforts could potentially be influenced by the study to include tactics, techniques and procedures surrounding training and logistics.
The Small Arms Ammunition Configuration Study evaluated commercially available small arms ammunition, emerging ammunition capabilities, and developmental ammunition technologies to address conventional and non conventional calibers used in carbines, rifles, and light or medium machine guns.
System studies showed that if the weapon system (ammunition, weapon, and fire control) are designed together in concert with Human Interface effects (recoil, weapon balance, and other metrics that can affect Soldier Aim error), then extremely significant improvements can be achieved. These significant enhancements are achievable because the improvements are synergistic in nature. As an example, if a new weapon system can increase the velocity of an existing cartridge (same projectile), the new weapon system extends the range in which the projectile’s lethal mechanism can be effective, and it also improves the probability of hit, P(H), as the flatter fire reduces the sensitivity to ranging errors that occur. When implemented with fire control, still greater improvements are possible, as the flatter trajectories can drastically reduce the demands placed upon the fire control to achieve the desired P(H). Therefore the synergies among the various weapon system component improvements could result in performances beyond anyone’s expectation.
Next Generation Squad Weapons, or NGSW, fires a 6.8 mm round. It would replace in the Close Combat Force the M249 and M4A1, both of which fire 5.56 mm rounds. Development of the NGSW is an outgrowth of the Army's 2017 Small Arms Ammunition Configuration Study, which showed the need for a new weapon. The Army tested several rifle prototypes produced by various companies and expected to field a new squad weapon in the latter part of 2022.
|
NEWSLETTER
|
| Join the GlobalSecurity.org mailing list |
|
|
|
