6.8 Western vs .277 SIG Fury: Cartridge Clash

In 2017 the U.S. military began solicitations for a new cartridge to replace the 5.56 NATO for the Next Generation Squad Weapon. It found what it was looking for in SIG’s 6.8x51. Its dimensions are similar to the 7.62x51 NATO—.470-inch case head, 2.83-inch overall length—but in place of the traditional brass case, the SIG case has a brass body, steel case head and aluminum locking washer.

The case design allows the SIG cartridge to attain pressures up to 80,000 psi, which is well above the safe operating pressures of brass-cased cartridges. SIG later released a “civilian” variant, the .277 SIG Fury.

In late 2021, Winchester released its own new .277 cartridge, the 6.8 Western. An updated .270 WSM with a .535-inch case head and a 2.020-inch case length, it accommodates extra-long projectiles in the 162- to 175-grain range, but its 2.955-inch overall length allows it to fit in a short action.

The goal was a short-action cartridge that fell between the popular, modern 6.5s—which many viewed as too light for elk and similar game—and the hard-kicking .300s. The 6.8 Western offers lower recoil than the 7mm Rem. Mag., .300 Win. Mag. and .300 WSM with similar or even better ballistics than those cartridges at 500 yards.

Not Apples-to-Apples

It’s not really possible to do an apples-to-apples comparison between the two. The 6.8 Western was designed for heavy-for-caliber bullets, while the .277 SIG Fury uses more traditional .277 bullet weights. Further, SIG lists velocities for its cartridge out of 16- and 24-inch barrels, but all the current sporting rifles wear 20-inch barrels.

The best we can do is look at the two closest loads and use 24-inch velocities since there are velocity data for both out of that barrel length. Those would be the SIG Hybrid Hunter for the .277 Fury, a 150-grain Nosler AccuBond (G1 BC .500) at 3,120 fps; and Winchester’s 165-grain Nosler AccuBond LR (G1 BC .620) for the 6.8 Western at 2,975 fps.

When zeroed at 200 yards, the .277 Fury holds a slight edge in trajectory—dropping 6.0 inches at 300 yards and 34.7 inches at 500 yards, compared to 6.3 and 36.0 respectively for the Western. But the increased bullet weight and ballistic coefficient of the Western begin to tell in wind drift and especially energy. Looking at just the 500-yard figures, the 6.8 Western drifts 13.4 inches while the deflection for the Fury is 16.1. The Western’s 165-grain bullet strikes with 130 more ft.-lbs. than the Fury—1,850 ft.-lbs. to 1,622.

There aren’t a ton of factory rounds for either one, but the 6.8 Western tops the Fury. Winchester/Browning offer six different 6.8 loads from 162 to 175 grains. Choice Ammunition’s offerings range from 150 to 170 grains.

High Pressures

SIG lists a 150-grain AccuBond for the Fury, along with a 135-grain full metal jacket. At press time, all were listed as out of stock, and that was the case for larger retailer websites as well.

The SIG cartridge is designed to operate in AR-10-style rifles like the MCX Spear while the 6.8 Western is strictly a bolt-action proposition. SIG does chamber the .277 Fury in its Cross line of rifles, and Seekins Precision has three bolt guns in .277 Fury. The 6.8 Western is available from Browning, Winchester, Seekins, Christensen Arms and Fierce Firearms.

Because the Fury operates at such high pressures, you can’t rebarrel a standard action for it and need to buy a gun specifically meant for it. However, even with its unique case design, the .277 Fury can be handloaded.

Which round is right for you? The 6.8 Western is a big game hunter’s tool that’s perfect for a day of long-range shooting. The SIG is perhaps more versatile because of the semiauto aspect, Seekins’ recent chambering of the .277 Fury tells you the cartridge isn’t just a proprietary anymore. Either way, it’s good to see a clash between new .277 cartridges.

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