The .277 FURY or 6.8×51mm, (designated as the 277 SIG FURY by the SAAMI) is a centerfire rimless bottlenecked rifle cartridge announced by SIG Sauer in late 2019. It utilizes a hybrid three-piece cartridge case that has a steel case head, brass body and a locking washer that mechanically connects the two to support a chamber pressure of 80,000 psi (551.6 MPa).
|Place of origin||United States|
|Produced||2019 (announced) to present|
|Case type||Rimless, bottleneck|
|Bullet diameter||.2780 in (7.06 mm)|
|Neck diameter||.3100 in (7.87 mm)|
|Shoulder diameter||.4611 in (11.71 mm)|
|Base diameter||.4703 in (11.95 mm)|
|Rim diameter||.4720 in (11.99 mm)|
|Rim thickness||.0540 in (1.37 mm)|
|Case length||2.015 in (51.2 mm)|
|Overall length||2.825 in (71.8 mm)|
|Rifling twist||1 in 7" (177.8 mm)|
|Maximum pressure (SAAMI)||80,000 psi (550 MPa)|
|Test barrel length: 16 inch (406 mm)|
The cartridge was designed by SIG Sauer for the United States Army’s next generation squad weapons program, officially known as the Next Generation Squad Weapon-Rifle (NGSW-R). The cartridge was announced for non-military usage along with the SIG Sauer CROSS—a bolt-action, magazine-fed rifle—in December 2019. In 2020 it was accepted by the Sporting Arms and Ammunition Manufacturers' Institute (SAAMI) as a new cartridge and chambering.
The cartridge uses a case that is the same length and diameter as the .308 Winchester. Each cartridge case consists of a stainless steel base coupled to a brass body via a locking washer. Stainless steel has a significant higher yield strength than brass, allowing the engineers to use higher Maximum Average Pressure (MAP) chamber pressure levels. Bullets are either 135 grains (8.7 g) "match grade" or 140 grains (9.1 g) "hunter tipped". The SAAMI warns that Maximum Average Pressure levels greater than 65,000 psi (448.2 MPa) may present increased risk of unsafe cartridge case or firearm rupture and thus require cartridge case and/or firearm designs that depart from traditional practices (materials, construction, and other design criteria).
The .277 FURY SAAMI (voluntary) Maximum Average Pressure (MAP) chamber pressure of 80,000 psi (551.6 MPa) enables a 135 grains (8.7 g) projectile muzzle velocity of 3,000 feet per second (914 m/s) from a 16-inch (406 mm) barrel. It also means that the .277 FURY should only be chambered in small arms that are capable of handling the accompanying bolt thrust safely.
SIG Sauer claims that the cartridge has performance superior to the 6.5mm Creedmoor, exhibiting 6 to 9 feet (1.8 to 2.7 m) less bullet drop at 1,000 yards (914 m), while delivering 20–25% greater energy.
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- NGSW Update: Push for the 6.8mm Continues
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- Maccar, David (2017-02-16). "The End of Brass Cartridge Cases?". range365.com. Retrieved 2020-11-29. CS1 maint: discouraged parameter (link)
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