.277 Fury

The .277 Fury or 6.8×51mm Common Cartridge,^[4][5] (designated as the .277 SIG Fury by SAAMI^[1]) is a centerfire rimless bottlenecked rifle cartridge announced by SIG Sauer in late 2019.^[2] Its hybrid three-piece cartridge case has a steel case head and brass body connected by an aluminum locking washer to support the high chamber pressure of 80,000 psi (551.6 MPa).^[2]

.277 Fury
Type	Centerfire rifle
Place of origin	United States
Production history
Designed	2019
Manufacturer	SIG Sauer
Produced	2019–present
Specifications
Case type	Rimless, bottleneck
Bullet diameter	.2780 in (7.06 mm)
Land diameter	.2700 in (6.86 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 in. (177.8 mm)
Maximum pressure (SAAMI)	80,000 psi (550 MPa)
Ballistic performance
Bullet mass/type Velocity Energy 135 gr (9 g) Hybrid match 3,000 ft/s (910 m/s) 2,694 ft⋅lbf (3,653 J) 135 gr (9 g) Elite ball FMJ 2,750 ft/s (840 m/s) 2,267 ft⋅lbf (3,074 J) 140 gr (9 g) VLD match 2,950 ft/s (900 m/s) 2,706 ft⋅lbf (3,669 J)
Test barrel length: 16 inch (406 mm) Source(s): [1][2][3]

Background

The cartridge was designed by SIG Sauer for the United States Army's Next Generation Squad Weapon Program (NGSW).^[2][6] It is dimensionally similar to the 7.62×51mm NATO service cartridge.

In December 2019, the cartridge was announced for non-military usage, along with the SIG Sauer CROSS bolt-action rifle. As a short-action rifle cartridge (cartridges having an overall length of 2.750 inches (69.85 mm) or less), increased internal ballistic performance for its cartridge case volume is accomplished by applying high gas pressure.^[7] In 2020, it was accepted by the Sporting Arms and Ammunition Manufacturers' Institute (SAAMI) as a new rifle cartridge and chambering.^[8] In 2022, SIG Sauer announced that it intends to commercially chamber the SIG MCX Spear semi-automatic rifle in .277 Fury.^[9]

Specifications

The cartridge uses a case that is the same length and diameter as the .308 Winchester.^[10] Each "hybrid" cartridge case consists of a stainless steel base coupled to a brass body via an aluminium locking washer.^[11][12] Stainless steel has a significantly higher yield strength than brass, allowing the engineers to use higher maximum average pressure (MAP) chamber pressure levels.^[13] Bullets are either 135 grains (8.75 g) "match grade" with a G1 ballistic coefficient of ≈ .488 or 140 grains (9.07 g) "hunter tipped" with a G1 ballistic coefficient of ≈ .508 (ballistic coefficients are somewhat debatable).^[12][14][15]

These projectile ballistic coefficients are equal to the publicized specifications of the Sierra .277 135 grains (8.75 g) HPBT MatchKing and .277 140 grains (9.07 g) TGK GameKing projectiles.^[16] The SAAMI warns that MAP levels greater than 65,000 psi (448.2 MPa) may present an increased risk of unsafe cartridge case or firearm rupture and thus will require new cartridge case and firearm designs that depart from traditional manufacturing practices, including the use of materials, construction methods, production lines, and other important design criteria.^[1][17][18]

The .277 Fury SAAMI (voluntary) 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.^[1][10] It also means that the .277 Fury is normally chambered in small arms that are capable of handling the accompanying bolt thrust safely.

Commercially, reduced-power .277 Fury Elite ball FMJ ammunition using non-hybrid conventional cartridge cases is offered, that fires a 135 grains (8.7 g) projectile with a G1 ballistic coefficient of ≈ .475 at a muzzle velocity of 2,750 feet per second (838 m/s) from a 16-inch (406 mm) barrel.^[3]

Performance

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.^[12][1]

Military award and designation as 6.8 common cartridge

An XM250 automatic rifle with inserted ammunition belt

In January 2019, the United States military began the Next Generation Squad Weapon Program to find replacements for the M4 carbine and M249 light machine gun. On April 19, 2022, the United States Army announced that it had selected SIG Sauer to build the XM7 rifle to partly replace the M4 carbine, while the XM250 automatic rifle was to replace the M249 SAW in the LMG role. In both cases it had selected the company's Fury ammunition, utilizing government provided projectiles and vendor-designed cartridges as the new weapon's ammunition.^[19][20]

The XM7 was designed to fire the 6.8×51mm SIG Fury cartridge in response to concerns that improvements in body armor would diminish the effectiveness of the 5.56×45mm NATO round used in the M4 carbine and M249 SAW and increase their lethality and effective ranges compared to common battlefield rounds such as the 5.56×45mm NATO and 7.62×51mm NATO.^{[21][22][23][24]}

Operational testing of the XM7 rifle, XM250 automatic rifle, XM157 fire control optic platform unit and the 6.8×51mm ammunition squad weaponry is expected to begin in 2024. However, this does not guarantee actual widespread future issue.^[25] The military designation for this round is 6.8 common cartridge.^[5] The XM1186 is the general-purpose 6.8 mm round, with other versions including reduced range rounds so weapons chambered in 6.8 mm can fire on existing ranges designed for the 5.56 mm, marking rounds for force-on-force shooting, and blank and tracer rounds.^[26]

Military solicitation

As of March 2022, the United States Army has a solicitation ongoing for an M240 machine gun 6.8×51mm conversion kit for the 7.62×51mm NATO-chambered M240B and M240L general-purpose machine guns.^[25][27]

References

1. "SAAMI .277 SIG FURY cartridge and chamber drawings" (PDF). Sporting Arms and Ammunition Manufacturers' Institute. 23 September 2020. Archived (PDF) from the original on 27 November 2023. Retrieved 25 November 2020.
2. Langston, Jay (20 December 2019). "277 SIG Fury: SIG Sauer Unveils New Caliber with Hybrid Case Design". Athlon Outdoors. Archived from the original on 3 October 2023. Retrieved 17 March 2020.
3. ".277 SIG Fury Elite Ball FMJ". SIG Sauer. Archived from the original on 14 December 2023.
4. Beckstrand, Tom (19 February 2020). "NGSW Update: Push for the 6.8mm Continues". Guns & Ammo. Archived from the original on 24 February 2020.
5. "Next Generation Squad Weapon Winner: Army Picks SIG SAUER". Athlon Outdoors. 20 April 2022. Archived from the original on 15 June 2023.
6. "SIG Cross Rifle". Xtreme Guns and Ammo. Archived from the original on 11 July 2023. Retrieved 8 March 2020.
7. Eger, Chris (19 December 2019). "New SIG Sauer CROSS Rifle, Company's 1st U.S. Made Bolt-Action Hunting Rifle". guns.com. Archived from the original on 15 June 2023. Retrieved 8 March 2020.
8. Moss, Matthew (21 November 2020). "SAAMI Announces Acceptance of Three New Cartridges from SIG Sauer, Weatherby and Winchester". The Firearm Blog. Archived from the original on 15 June 2023. Retrieved 25 November 2020.
9. Graves, Eric (13 January 2022). "SIG SAUER Announces Commercial Variant of Army Next Generation Squad Weapon (NGSW) MCX-SPEAR and 277 SIG FURY Ammunition". Soldier Systems. Archived from the original on 27 September 2023. Retrieved 23 April 2022.
10. Spomer, Ron (26 February 2020). "The New 27 Nosler and .277 Sig Fury Are Creating a .277 Cartridge Comeback". outdoorlife.com. Archived from the original on 29 September 2023. Retrieved 17 March 2020.
11. Sim, Levi (22 December 2019). ".277 SIG Fury Demystified". gunsamerica.com. Archived from the original on 15 June 2023. Retrieved 17 March 2020.
12. SIG Sauer Product Catalog. SIG Sauer. 2020. pp. 70–71. Retrieved March 17, 2020.
13. "SAAMI Certifies .277 Sig Fury Cartridge with Incredible Chamber Pressure". pottsprecision.com. 16 November 2020. Archived from the original on 3 June 2022. Retrieved 29 April 2022.
14. "277 SIG FURY, 2 Other Cartridges Accepted by SAAMI". Athlon Outdoors. 16 November 2020. Archived from the original on 15 June 2023. Retrieved 29 November 2020.
15. "Comparing Advertised Ballistic Coefficients with Independent Measurements" (PDF). Schweizerische Mittelkaliber-Schützengesellschaft. 17 January 2012. Archived from the original (PDF) on 21 March 2023. Retrieved 30 April 2022.
16. "Ballistics Coefficients Charts - Rifle" (PDF). Sierra Bullets. Archived (PDF) from the original on 21 November 2023.
17. Maccar, David (16 February 2017). "The End of Brass Cartridge Cases?". range365.com. Archived from the original on 3 June 2022. Retrieved 29 November 2020.
18. Dykstra, Greg (19 July 2016). "Understanding Pressure". primalrights.com. Archived from the original on 16 June 2023. Retrieved 29 November 2020.
19. "Army awards Next Generation Squad Weapon contract". U.S. Army. 19 April 2022. Archived from the original on 11 January 2024. Retrieved 19 April 2022.
20. "ASIG Ammunition Produced & Delivered Over 825,000 Rounds of 6.8x51mm Composite Case Ammo for US Army Next Generation Squad Weapons Program Prototype Test #2". Soldier Systems. 21 January 2022. Archived from the original on 15 June 2023. Retrieved 22 April 2022.
21. South, Todd (19 April 2022). "Army chooses Sig Sauer to build its Next Generation Squad Weapon". Army Times. Archived from the original on 18 May 2023. Retrieved 20 April 2022.
22. Schogol, Jeff (19 April 2022). "Army selects Sig Sauer to produce Next Generation Squad Weapon and ammo". Task & Purpose. Archived from the original on 31 May 2022. Retrieved 20 April 2022.
23. Sensiba, Jennifer (21 April 2022). "The XM5 and 6.8×51 Ammunition Will Be a Decisive Advantage. U.S. Allies Should Adopt It, Too". The Truth about Guns. Archived from the original on 7 December 2023. Retrieved 24 April 2022.
24. Mizokami, Kyle (21 April 2022). "The Army's Next-Gen Infantry Weapons Will Be More Lethal and More Accurate". Popular Mechanics. Archived from the original on 31 May 2022. Retrieved 24 April 2022.
25. Parsons, Dan (20 April 2022). "Here's Everything We Now Know About The Army's New Squad Rifles". The Drive. Archived from the original on 27 November 2023. Retrieved 30 April 2022.
26. South, Todd (6 October 2023). "What's the firepower like for the Army's new rifle?". Defense News. Archived from the original on 15 January 2024.
27. "M240 6.8mm Conversion Kit". sam.gov. 31 March 2022. Archived from the original on 15 January 2024.

External links

• New for 2020: SIG Sauer .277 SIG Fury Ammunition via YouTube (Archive)
• .277 SIG Fury SAAMI Drawing Archived June 11, 2023, at the Wayback Machine