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History of the Sig 277 Fury

Along with 2 new badass guns (the XM5 "Spear" Rifle and the XM250 LMG), Sig has developed the new 277 Fury caliber round to go with it. This is the first time since WW2 that the U.S Army has adopted both a new standard issue weapon and a new caliber of ammunition.

You're probably thinking "Why do we need this...Is this what my tax dollars are going to?", well here is the reason. In 2017 the Army conducted a study called the Small Arms Ammunition Configuration Study which basically concluded that the 5.56 NATO did not have the stopping power necessary to punch through the advanced armor of our near-peer adversaries (Russia, China, and Iran probably) at long range. Based off this study the Army realized they wanted a round that can hold a 6.8mm cartridge and still blow through advanced body armor at 500 meters. Now that sounds like a tall order but Sig absolutely delivered during the Army's proceeding weapons trials, A.K.A the Next Generation Squad Weapon Program (NGSW) in 2018. Sig swept the competition and the XM5, XM250, and the 277 Fury won the contract. Enough of the history lesson, lets get on with the ballistics.


277 Fury Ballistics

Just at a glance you can see the .277 Sig Fury is a really unique round. First thing you'll notice is that it has a bi-metal casing which has a steel metal base and brass body. The metric dimension of the Fury is 6.8x51mm, which is a big boy. Standard .277 Fury ammo holds 140 grains. This means its over twice as powerful as the standard 62 grain 5.56 NATO round. This high power round has a chamber pressure of 80,000 PSI, which is practically unheard of for any military ammunition. For comparison, the 5.56 NATO goes out at about 62k PSI and the 7.62x51 NATO is at 60.2k PSI. Having 18-20k more PSI coming out of a barrel is a ridiculously huge advancement in stopping power. This means the .277 Fury has a Muzzle Velocity of 3,000 FPS put of a 16in barrel. Essentially this round is just a magnum version of a 6.5 Creedmoor on steroids. While the 6.8 SPC is currently widely available, it is not the same as the 277 Fury. The 6.8 SPC (or 6.8x43mm) was made for the AR-15 platform. 277 Fury is too large to fit into any standard AR-15 platform. While these rounds have a lot in common, the .277 is an absolute monster. Here is a chart comparing the 277 Fury to the 5.56, 300 Winchester, 308 Winchester, and the 6.5 Creedmoor.

Civilian Use of the .277 Fury

Well here is the bad part... As of November 2022, the only civilian model rifle that can chamber the 277 Fury is the Sig Cross Rifle. Allegedly, Sig is also going to make a 277 Fury version of the MCX Spear (which is essentially the civilian version of the XM5) sometime within the next year. Production of this new cartridge is pretty slow considering most of it is going towards the Army's NGSW testing. Lake City, the largest ammo producer for the military, is said to start mass production of the round in 2023 which will allow Sig and other firearm manufactures to produce more guns chambered in 277 Fury. This could ideally be used as a Hunting round for all you long distance hunters out there. While its ballistically better than the 6.5 Creedmoor, it might not replace this popular hunting round. Knowing that you need 2,000 FPS or 1,000 ft.lbf to hunt ethically, a 277 Fury can deliver that out to 800 yards while the 6.5 Creedmoor can do the same at 600yds. 200 yards does sound a lot cooler in theory, but hunting game at 600 yards is outside most peoples personal limits for hunting. With all that said, I'm still going to get one as soon as their available. I personally love long range target shooting and I think this would be awesome to have in my range arsenal.


As a Soldier, this round is going to be absolutely game changing on the battlefield. Even though I doubt I will get my hands on one in my remaining time in the service, this innovation will help better the tactics and capabilities in the future. Giving soldiers longer range capabilities will give us the upper hand in any future conflicts that may arise. And as for the civilian market, firing a 277 Fury will definitely be a blast at the range. I myself plan on getting a 277 Fury capable firearm to take long range target shooting or maybe take on my next elk hunting trip. For now we'll just have to wait, but in the future I think this round will rock the firearm industry.