
.277 FURY

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 .
Background.
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.
Specifications.
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 "match grade" or "hunter tipped".
The SAAMI warns that Maximum Average Pressure levels greater than 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 enables a projectile muzzle velocity of from a 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.
Performance.
SIG Sauer claims that the cartridge has performance superior to the 6.5mm Creedmoor, exhibiting less bullet drop at , while delivering 20–25% greater energy.