277 Sig Fury


I just learned of this round this evening.
It has a 2-piece case, with the head made of steel to to handle higher pressure.

I’ll look for it at SHOT next month.

Interesting, SIG is going full speed ahead with their composite case design.

Cropped photos of the .277 SIG Fury cartridge taken from: http://soldiersystems.net/2019/12/18/sig-sauer-announces-new-bolt-gun-and-caliber-sig-cross-277-sig-fury/

.277 SIG Fury

.277 SIG Fury, a

Below is the 6.8x51mm SIG, 2019, for SIG’s Next Generation Squad Weapon R&D program entry with composite case. See: Sig Sauer 6.8mm Next Generation Squad Weapon cartridge


My guess is that as .277 inches is the equivalent of 6.8mm, Sig is simply renaming the military 6.8x51 to be the .277 Sig Fury.

Much like the 223 Rem and 308 Win.

Sig gets to brand their own name on a round, and its good for the metric-phobic US gun owner too!

Thanks for sharing.

I’ve looked and I cannot find bullet weight anywhere… Impressive velocity for 16 inch barrel.

A quote from my forum:

This added pressure will drive a 135-grain bullet from SIG’s Hybrid Match cartridge 3,000 fps from a 16-inch barrel , and produce 2,694 ft.-lbs. of energy. The 135-grain bullet has a respectable .488 G1 BC.

SIG’s 277 Fury Hybrid Hunting load features a 140-grain bullet with a .508 G1 BC, launching from a 16-inch barrel at 2,950 fps. That one produces 2,706 ft.-lbs. of muzzle energy, too.


It’ll be interesting to see if this gets adopted for sure… I mean there is also NATO… Not sure how we could go it alone… Most of those countries wouldn’t be willing to upgrade because of costs I’d bet.

Photos of SIG preproduction .277 SIG Fury hunting round (no headstamp) with a 140gr bullet.
Photos from the article .277 SIG Fury Demystified, https://www.gunsamerica.com/digest/277-sig-fury-demystified/

Left 6.5 x 49mm Creedmoor, .277 Fury center, .308 Winchester on the right.

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Good info in the Guns America article. Thanks for posting.

I wouldn’t worry. The US adopted the 5.56 mm about 15 years before NATO did (and some NATO countries waited for a long time after that before changing). The US Army will pick whatever they want and the rest of NATO will probably follow suit, sooner or later. Unless, of course, they are unconvinced by the idea of a magnum-class cartridge in the standard infantry rifle.

The article shared by Brian (Thank you!) is quite confident about the reality of 3000 fps of a 140 gr bullet from a 16" barrel (914 m/s, 9.07 g, meaning 3790 J,from 406 mm). No wonder they assume pressure at “more than 80000 psi” (5500 bar).
I look forward to the official SAAMI specification and what life span barrels and rifle bolts will have if this pressure figure is true. The Cross rifle has a very massive bolt head. But rebarreling existing rifles for a cartridge with this pressure (if correct) looks outright dangerous to me.

Reading between the lines (as a layman) I see the next cartridge debacle coming?

You mean “Can I fire 6.8 x 51 ammo in my 277 Fury rifle?” posts for ever more?

No, not the confusion of ignorant people but issues with the ammo/gun system after adoption when all sort of obvious drawbacks and problems will come to light which for some reason were not adressed before. Actually I have the M16 story in mind.

I think that Sig is pushing this now in order to generate interest at the Shot Show. Seeing a lot of ads for the Sig Cross rifle. Did not know what the 277 Fury was until I looked it up.

While not as short as the 5.56x45, the 6.8x51 is still a short throw but has magnum energy. The 277 Fury, if adopted by the Army, will make a great hunting round.

True Velocity is also pushing their round for the Shot Show.

2020 Shot Show video, sectioned SIG .277 Fury demonstration cartridge which looks to be about 2 feet tall in the video:

Closeup of the sectioned cartridge base:

Same photo as above, parts identified:

YouTube video with the SIG .277 Fury demonstration cartridge