.277 Sig Fury (6.8x51): Ballistics, Vs. 5.56 and .308, and The Future

6.8x51 bullet
May 17, 2022 Edited June 4, 2024 90676 view(s)
.277 Sig Fury (6.8x51): Ballistics, Vs. 5.56 and .308, and The Future

In the news off and on for over 5 years, the hammer has finally dropped and the US Army as choisen Sig Sauer’s .277 FURY as their new cartridge for the NGSW program!

What does this mean for the venerable M4? Is the AR-15 dead? Are we all going to switch to 6.8mm? Let’s talk about it.

XM5 and XM250


Important History

You might be wondering where this all came from, thankfully the answer is pretty simple.

Back in 2017 the Army did a study called the Small Arms Ammunition Configuration Study and that study concluded that while the M4 was a great rifle, it and 5.56 NATO did not have the punch required to defeat near-peer (Russian and Chinese most likely) armor at long range.

At least, that is what we’ve been told that the study says. The study itself is still classified, so we’re not exactly sure what it exactly says.

The study, we’re told, concluded that a new ammo type was needed, that it should be 6.8mm, and that a new rifle system would be required.

Based on this information the NGSW Program was started in 2018.

The requirements for the program haven’t been released to the public, but snippets of information have come out. Basically, the Army wanted a 6.8mm cartridge that could defeat near-peer armor at 500 meters.

Many entered, a few were selected, but the final winner was recently announced as being Sig Sauer with their XM5 rifle, XM250 LMG, and the .277 SIG FURY (6.8x51mm) cartridge.

The XM5 is Sig’s MCX Spear rifle (basically a MCX Virtus scaled up from 5.56 NATO to 6.8x51mm) and the XM250 is Sig’s MG-338 that SOCOM is testing but scaled down a little from .338 Norma Magnum to 6.8x51mm.

But enough with that stuff -- let’s talk cartridge.

.277 Sig Fury Diagram

.277 Fury/6.8x51mm Is Not 6.8 SPC

For some reason, some sources have started to claim that 6.8 SPC is the same thing as what the Army just adopted.

This is wrong. Very wrong. Not even remotely close to being true in any known realm of reality.

Just to be clear here -- 6.8 SPC is 6.8x43mm and is designed for the AR-15. .277 Fury, the cartridge that was just adopted, is 6.8x51mm and is much too large to fit in a standard AR-15 frame.


The 6.8x51mm is a horrible name in my opinion. Thankfully, Sig submitted the design to SAAMI under the name .277 SIG FURY and that’s much cooler.

.277 SIG FURY is a really… odd cartridge.

Right off the bat it has two things that REALLY make it stand out -- first, it’s a bi-metal case. The base is made from stainless steel and the body is made from brass. The two use a locking washer to mate together.

The other thing is that according to Sig and the Army 6.8x51mm has a chamber pressure of 80,000 PSI.

To put that into context, very few cartridges go over 60-62k PSI. 5.56 NATO is 62k PSI (NATO method) and 7.62x51 NATO is 60.2k PSI (NATO method).

That means .277 SIG FURY having 18-20k PSI higher is… a lot. Like, a HUGE lot.

That pressure, according to the Army and Sig, means .277 SIG FURY shoots a 140gr bullet at 3,000 FPS from a 16” barrel. That’s wicked cool.

Ballistically, I think this is easiest for us to picture it as basically a magnum version 6.5 Creedmoor.

Side by side there are a lot of similarities, just that .277 SIG FURY is juiced up.

Check out this chart:

Ballistics chart for 227 Fury vs others

The chart makes it clear, .277 SIG FURY has a huge advantage over a lot of common cartridges when it comes to drop.

To make this even clearer, here is a chart:


Barrel Length

Bullet Weight

Muzzle Velocity

Energy @ 100y

Energy @ 500y

Drop @ 500y




3,000 FPS

2,529 ft.lbf

1,654 ft.lbf

-41 inches

6.5 Creedmoor



2,710 FPS

2,056 ft.lbf

1,317 ft.lbf

-53 inches

.300 Win Mag



2,960 FPS

2,947 ft.lbf

1,378 ft.lbf

-52 inches

.308 Winchester



2,700 FPS

2,356 ft.lbf

1,264 ft.lbf

-59 inches

5.56 NATO 




1,080 ft.lbf

512 ft.lbf

-54 inches

If the Army goes through with their plan .277 SIG FURY is going to replace the M4 and M855A1 cartridge.

Ballistically, these aren’t remotely comparable. However, it should be noted that we are comparing an intermediate cartridge with a full-sized cartridge. Adopting .277 SIG FURY basically means we’re going back to the days of big cartridges.

If that is actually a gain for our warfighters… well, that’s for another article.

Regardless, speaking purely in terms of ballistics -- .277 SIG FURY is a beast.

6.8x51 vs. 5.56


As you can see from the charts above, the comparison between 5.56x45 and 6.8x51 is not close ballistically. Consider the starting velocities and bullet energies. A 140 grain projectile is more than twice as big as a 62 grain. Obviously true. Now add to it that 6.8x51's bullet exits the muzzle at 3,000 fps which is 200 fps faster than 5.56. These are rather generic velocities and averages but will suffice for what we’re doing.

Those two measurements have a direct bearing on bullet energy. At the muzzle, the 5.56 shows 1080 ft/lbs of energy, while the 6.8/277 shows just shy of 2,800. Look on down to 500 yards. The 5.56 has fallen to just over 1,900 fps with 512 ft/lbs of energy and dropped about 54 inches, not quite 5 feet. Compare that to the 6.8x51 at 2,091 fps and about 1,400 ft/lbs, with a drop of only about 46 inches. Remember… this smaller drop is accomplished with a bullet over twice as heavy as that of the 5.56mm. 

It’s no wonder that our soldiers will most likely be glad to get this cartridge. It will speak with far more authority than the current 5.56mm and will enable meaningful hits on targets at ranges up to and past 500 yards. The 6.8x51 has more energy remaining at 1,000 yards than the 5.56 does at 500.


This will be quick. What are the recoil energies for the pair, given the data above? 6.2 ft/lbs for the 5.56 and almost 19 for the 6.8x51. These are more “guesstimates” than hard facts, but I went with what numbers I could find. Suffice it to say, the 6.8x51 will kick a lot harder than the 5.56. 


Also, consider the weight of loaded ammo. The 6.8x51 will weigh approximately three times what a similar number of 5.56mm rounds weigh. That cuts down on the amount a warfighter could carry on the battlefield. I don’t know for sure, but I would imagine the Army powers-that-be are hoping that the 6.8 will be more effective and require fewer rounds than the 5.56 to get a particular job done.

Chamber Pressure

As for chamber pressure, the civilian .223 is loaded to (psi) 55,000. The 5.56x45 NATO goes up to 58,000. The winner? The 6.8x51, at a whopping 80,000 psi. SAAMI gave special dispensation to allow this high number… no other commercial cartridge is so loaded. Even the .338 Lapua tops out at around 61,000. All this means that the .277 Fury is king of the pressure hill. 

6.8x51 vs. .308

Ah… here, the difference isn’t so clear-cut. The difference between the two is less than that of the 6.8x51 and the 5.56. You have the same case dimensions for both (even though the 6.8 is a hybrid case), so the powder capacity is roughly the same. You have a bullet diameter difference of .239 inch… .308 minus .277. The cartridges should be pretty similar, right? You’d think so.

Take a look again at the chart above comparing 6.8x51 (.277 Fury) and some other common cartridges. All five are fairly close at 400 yards, but then things start to happen. Cutting to the chase, the (purple line) .308 shows a final drop at 900 yards of about 25 feet, while the (green line) .277 Fury drops about 16 feet at that distance. Given the fact that the Fury’s bullet started at around 3,000 fps, it isn’t rocket science to figure that the bullet from that rifle would retain energy and show less drop than any of the other calibers shown here. The ballistic coefficient of .277 Fury's 140-grain bullet is higher than that of the .308 so it will hang on to velocity at longer ranges. 

This chart reflects the main advantage the .277/6.8x51 has… oomph. That’s a "technical term" for lots of velocity and lots of energy at ridiculous ranges. The .308 is used as a sniper rifle, but with the advent of this baby, I can see military agencies making the switch. I mentioned above that the Fury is designed to defeat modern body armor at 500 meters. This would give our military a huge bonus, which leads me to the last section…

What .277 Fury Means For You

.277 Fury Loaded in Magazine

Right now -- probably nothing.

The Army wants to replace at least part of its inventory of M4 carbines and M249 SAW's with their Sig counterparts. This is slated to start occurring by October of this year. But, not all the 5.56mm firearms will be gone. From what I read, the Army is only issuing the new 6.8s to actual combat troops. Rear-area and other non-front-line troops will still carry the M4.

Production for this new cartridge is very low and very slow. What little Sig is producing is almost all going to military testing. Other brands can make it if they want, but so far almost no one is.

Lake City, the military’s ammo manufacturing plant, is gearing up to produce 6.8x51mm but that won’t be online until 2023/2024. After that, Sig will become the secondary source for ammo to the military.

When it does become more available I’m still not sure what role it might fill.

It won’t be cheap to shoot, surely not cheaper than .308 Win or 6.5 Creedmoor.

While it will be ballistically better than 6.5 Creedmoor, I’m not sure that it is better enough for it to really matter for most of us.

Using the generalization that you need 2,000 FPS and/or 1,000 ft.lbf for hunting ethically, .277 Fury delivers that out to 800 yards. 6.5 Creedmoor delivers that to about 600 yards.

200 more yards might sound cool, but even 600 yards is way outside most people’s personal limits for hunting.

I’m sure there will be an appeal for what is effectively a 6.5 Creedmoor Magnum, but I’m not sure that it will actually replace or change much for the majority of us.

That said -- I still totally plan on getting one when I can.

Shop 5.56 Uppers

Is The AR-15/M4 Becoming Obsolescent?

No. It is not. There are a lot of reasons why so let’s talk about it.

The Army is looking to replace their M4s and M249s for warfighting reasons. But they’ve also been trying to do that for a long, long time. Nothing has ever come of it. Yet.

Personally, I doubt that the Army will get rid of the M4 in my lifetime. The platform is too useful, too good, and too cheap.

Even if the Army does, that won’t change anything for the average AR-15 owner. While there is no debate that 5.56 NATO struggles at range, no average home defender is needing to punch through space-age body armor at 500 meters.

For 99% of people facing 99% of problems, the AR-15 is and will remain the most practical and useful platform.

Sig 277 Fury Ammo

Wrapping Up

There is still a lot of speculation in the air about .277 SIG FURY, the XM5, the M4, and a lot more. For now, nothing is really happening except that the Army is spending a ton of money to test things out.

For now, business as usual for most of us. But give it a few years and we might be in for a big shake up.

[While you're here, check out our selection of AR-15, AR-10, and AR-9 rifles, uppers, barrels and more! We manufacture 16 calibers of pistols and rifles here in Sanford, NC and cut out the middle man to pass on the savings to you. Shop your next build here!]


Please login to comment.

Don't have an account?

Sign Up for free
Danny M. Rogers ADCM
May 18, 2022
Great info. and stats, thanks
Bruce R. Williams
May 18, 2022
very interesting, might be just the thing for shooting robots . but for now the 6.5 creed will make a average shooter into a good shooter with a little practice . the 277 fury sure sounds cool though.
Dwayne L Daniel
May 19, 2022
With that much pressure I'm curious how a two part casing will hold up. If and when it becomes readily available to the public, its not going to be good for reloaders.
Bob Peters
May 26, 2022
Military only cares about one shot. Not a reloading issue like for people like us.
October 7, 2023
Have you not been in the military? You police all range brass and reload like crazy, I'm guessing that was a requirement with any new round they adopted.
Roger Bainbridge
September 27, 2022
The two piece 9mm alloy/aluminum cases are extremely durable and have been successfully reloaded over 30 times.
Steve sale
May 20, 2022
Are y'all going to build an upper for the 277 fury??? How bout building a 7mm08
May 23, 2022
Make sure you sign up for our newsletter (https://www.bearcreekarsenal.com/bca-subscribe) to keep abreast on all upcoming products and sales.
April 7, 2023
because 7-08 is terrible
October 7, 2023
Really 7-08 is terrible? It carries almost the same ballistics as 6.5 creedmore with larger bullet choices. After researching it 7-08 is what everyone should have geeked out about not 6.5CM.
Jon Gross
October 20, 2023
Steve, You're a bad man! Never thought of a 7mm-08 upper. Now, my mind is going crazy. While we're at it, how about a .......257 Roberts!?!?
Andrew Waring
May 20, 2022
Could that case launch a 308 bullet to 30-06 and above capabilities
May 20, 2022
That depends on what you're meaning by .30-06 levels. If we're comparing to the classic loadings of 70+ years ago then many modern .308 loads already beat them. Truly modern .30-06 loads are general always going to outpace .308 by 100-300 fps due to case capacity differences. In the end you're still going to be limited by the chamber pressure firearms in .308 are designed to handle which is NOT the 80,000 PSI they are claiming with this style of case. In theory with the right action could it be done? Yeah, but my question is why would you want to try when .30-06 rifles and ammo are readily available, often moreso than their .308 counterparts in my experience.
mike sauer
May 21, 2022
will you be comming out with a complete AR-10 277 fury upper
May 23, 2022
Make sure you sign up for our newsletter ( https://www.bearcreekarsenal.com/bca-subscribe) to stay up-to date on new releases sales and returning products.
Michael Urban Sr
June 12, 2022
Hey thats not an answer?lol So are you guys going to produce civilian variants? I am just starting a new build ,which is a 6.8SPC but thats not the same round obviously! LOL So yes i would love to see you guys come out with a 6.8Fury?!?!?!? WHEN?????
October 7, 2023
I'll almost guarantee they will, they already have the biggest line of calibers I've seen, once ammo is being mass produced this is the round to have with military surplus being that of .308 and 5.56 eventually.
May 22, 2022
Great Article, thank you!! Questions....... Is this platform a fire n forget? Is this cartridge reloadable? Based on the 2 piece design, would you even want to reload it? No doubt they feel the brass will fail at the stratospheric pressure. At $2/cartridge cost, if this is not reloadable, it will eliminate most of the civilian demand. JMHO
June 4, 2022
Why wouldn't it be reloadable? It'll be easy to pick up on the range with a magnet, which is a side benefit too.
Greg R.
May 23, 2022
David, what happened to the 6mm ARC? Useable in an AR15/M4 design, 103-108 gr bullets presently and great ballistics compared to 5.56mm. Maybe not the energy of this new cartridge at distance, but more effective than 5.56mm for everyday use. Seems the .277 Fury is more of a sniper round. Hope this isn't another waste of taxpayer $$$!
Michael Urban Sr
June 12, 2022
HAHAHA thats what the military and our Fed Gov is known for! LOL Of course its a waste of tax payer cash! The Fed already takes money from our SSI fund that "we the people" pay into , and the politicians never pay it back. Then claim that the fund may have to be done away with because ,there isnt enough money in it....Well if the corrupt and crooked politicians paid back when they "stole" from us ,then it wouldnt be an issue! So for the Fed and military to wate our money isnt anything new or uncommon! All i know is im getting as many firearms and ammunition as i can before the new "unconstitutional" laws are being imposed on the people! Everyone seems to bend a knee when the illegitimate president /admin as well as congress and senate "unconstitutionally" impose new laws upon us all.....? I for one plan to carry a copy of our Constitution as it was 1st written with me so when the police and military try to enforce these unconstitutional laws on us! I will never submit to the left or its "unconstitutional" policies,regulations and laws! They can piss off!
Col Lane Crawley
May 4, 2023
The ARC is Growing leaps and bounds. Covid slowed it down at first but its roaring now.
M Payton
May 25, 2022
I think would work very well in the M134 Minigun on our helicopters, some serious extended range whoop-ass
M Payton
May 25, 2022
The recoil should be around 18-22lbs of kick according to Chuck Hawks recoil table https://www.chuckhawks.com/recoil_table.htm, the .270 Win 140gr@3000fps has 17.1lbs for an 8lb gun, but that being 7.62x63 not x51 and out of a 20-24" barrel not 16" barrel, they must be using a really fast burning powder.
Mike Simpson
May 25, 2022
Thanks for the comments on the Sig Fury cartridge. I think is will kust end up being an huge waste of money to the military and seems really politically motivated. I own numerous products you produce and have had ZERO ISSUES with any of them. I will continue to support you in the future. It is nice to know that Sanford NC produces great products that are used by gun enthusiasts around the USA. Keep up the good work!
Michael Urban Sr
June 12, 2022
I totally agree! I do have ot admit i didnt wait for a Gen2 ,rather i purchased BCA's 1st Gen AR47 lol Then it sat in my safe for over a year as i was very busy with work and family. When i finally took it to the range it didnt run LOL The firing pin was striking the round but not igniting it....So i contacted BCA almost 2yrs after purchasing the upper and they had no issues sending me a firing pin to replace the one i had. They had figured out by the time they came out with their Gen2 AR47's that they needed a robust pin to ignite the steel cased rounds. I still have not had the time ot put in the new pin to get it running but it sure looks good! LOL But the 6.5 Grendel upper i purchased it a tac driver! I just love it and its my 2nd most favorite AR's now! i just wish i would have gotten it with a 20" barrel rather then a 16"? :>/ LOL Now when it comes to the 6.8Fury i plan to own one if they are ever made available to the public? FOR SURE!!! :>)
October 7, 2023
I had this happen in a ceratac build and bought a titanium firing pin, then had it happen in my BCA build, I 100% recommend first thing upgrading firing pins in these budget builds. Just order a bunch of pins and don't even shoot a round with the budget ones.
November 16, 2022
The US military is preparing for land warfare against a near-peer enemy. I can think of one that could easily field an army 10 times as large as the US Army. If I were go to war with that Army I'd want a superior direct fire rifle, which this is. This is a serious leap in technology vs other attempts to develop a better gun. I suspect the US is going to go from a 3 cartridge Army (5.56, 7.62, .50BMG) to a 5 cartridge army (add in 6.8x51 and .338 Norma Magnum). Everyone and their mother has M4's now. The US Army needs this if it wants to stay ahead.
October 7, 2023
How will these be a failure? The ballistics on this thing are amazing. Politics and tax money is the reason we ended up with the 5.56 and I guarantee it has caused many a soldiers life. The only logical conclusion of why they settled on 5.56 is cheap cheap cheap. After growing up shooting way better calibers then joining the Army it always felt pathetic shooting that toy round. Pretty scary to think everyone was shooting back with something that was walloping three times as hard.
December 12, 2023
It is much more intelligent from a budget and logistics standpoint to simply change the upper in the existing M4s and M16s for a 6ARC, 6.5 Grendel or even as a wild card...the .400 Legend. All can fit 25rds where 30rds of 5.56 fit all are a huge increase in power, realistically the Legend is the best thing possible for sub 300yds, it's like a 10mm super magnum, if 25rd mag become available I would want it as my main upper with 6arc or 6.5G for long range use, probably more justifiable in conditions west of the Mississippi. This 6.8x51 is stupid, the rifle is big and heavy, the ammo is big and heavy, the recoil and muzzle jump is heavy, less maneuverable, too expensive, too specialized, poor for run and gun operations, poor for light infantry, poor for close combat. This new rifle and round is something I would have been excited about 21yrs ago when I was a buck private,now with age a d wisdom I know for a fact that simply putting an .eaner round in the AR-15 pattern is better for everyone for every reason.
Bob Peters
May 26, 2022
Well , don't see it in my future but I will enjoy following the progress. Basically a .270WSM on a .308 case at high pressure. If I could find some one to make an LR308 barrel in .270WSM chambering I could do it now. Or even 7mmWSM would be nice. Anybody at BCA listening? Need more choices than .308 and 6.5 CM. What a great time to be building ARs, eh?
May 26, 2022
I just ran the ballistics for .308 on the Hornady ballistics calculator. .308 150 gr hornady SST bullet. You can get 3000 fps out of a .308 with that weight projectile with certain modern propellants. The 308 out performs the sig furry. 300 yard zero: 500 yard ft lbs 22.9 inch drop 2,008 ft lbs velocity 2,456 fps, 1000 yards 1,291 ft lbs 1,969 fps.18.3 ft at 1000 yds. At a 100 yard zero the 308 has similar bullet drop and more energy. They say they have a special treatment for the barrel and it is easy to change. Might need to be at that pressure. See if it burns out barrels? Good article I enjoyed it. May want a civilian version when the price becomes reasonable. Might be a good deer and black bear cartridge just with a all brass case and lower pressure. Just need a proper bullet for the game you are hunting. Many people use a .270 to deer and elk hunt. This is in a similar range.
December 12, 2022
you cant shoot it as fast. Thats the point.
Eric Todd
May 29, 2022
May not be about .277 fury but I'd really love to see a 7.62x39 dedicated lower that accepts AK-47 magazines from y'all. I have so many great ideas to improve and further y'all's brand.
Michael Urban Sr
June 12, 2022
LOL yeah i think they should take some of our suggestions! I have already asked BCA long ago for them to make an AK rifle. The closest they came was their AR47 lol With the Fed stripping us of our 2A rights i dont think for a minute ill ever be able to buy an AK47 or AK74 for that matter? I started off loving Ars so much i wanted an AR15 in every caliber. I came close but my wife started complaining hehe so theres just a few i didnt build. But i told her i want one AK47 and one AR10 before i stop growing my collection! But now i dont think im gonna make it? :>( Mainly because companies that build firearms obey the unconstitutional laws of the Fed Gov! I mean it states right in our Constitution that any and "all" policies,regulations and laws imposed on the people are automatically Null&Void yet the companies and people still obey and follow them......? WE THE PEOPLE must stand for our rights and stop bitching threw the computer! We need ot get out in the streets and march for our rights to keep them! Once lost we will "never" get them back! HELLO? Sorry im not bitching at you but i prya every gun owner and ,free American get out and vote as well as protest that our rights are our rights and they ave no right to take them away!!! NOW!!!!!!!
Willard Greenup
May 29, 2022
While the Fury is intriguing. the cost of ammunition will be prohibitive for the average Joe on the street. Secondly, while I like the 6.5 Creedmoor and the 6.5 Grendel, I am a die hard believer in the 6.5x55 Swedish loaded in a strong action, being on par or excelling performance of the Creedmoor. Just for kicks, I would love to see you produce the .17 HMR barrel and bolt for some of us that just plain like to shoot the crap out of stuff like cans, filled jugs, squirrels, coyotes and prairie dogs.
Kenn Olsten
May 29, 2022
Thank you for the article. Very informative; answered a lot of questions. Good research.
May 29, 2022
Thanks for the info. Just heard about this tonight from a fellow church member who is also a deputy sheriff who follows gun stuff. Googled more info and found this article. May be a possible LR308 upper one day. Especially being able to go with a 16 inch barrel and still getting crazy velocity. Jesus Saves!
June 5, 2022
When will you all produce a barrel for .277 fury?
June 6, 2022
To stay up-to date on all upcoming sales and new products release make sure you sign up for our newsletter (https://www.bearcreekarsenal.com/bca-subscribe).
Michael Urban Sr
June 12, 2022
Id like to know that my self? I already purchased all i need for my 6.8SPC but thats just not the same round! LOL
June 10, 2022
Will there be an .277 Fury upper for AR-10s?
June 15, 2022
For new releases and upcoming sale make sure you sign up for our newsletter (https://www.bearcreekarsenal.com/bca-subscribe)
Michael Urban Sr
June 12, 2022
So when do you guys plan to build a rifle and some uppers in this caliber?
June 15, 2022
For new releases and upcoming sale make sure you sign up for our newsletter (https://www.bearcreekarsenal.com/bca-subscribe)
John R. Shirley
June 16, 2022
I see the .277 Sig Fury becoming a crew-served and SDM rifle. It might be adopted by some Special Operating Forces, but when it's rolled out to the force as a whole, it won't last. Rather like the M14, only more powerful.
June 21, 2022
I wonder why the 30-06 shot from a Garrand was not part of the comparison.
Ray Odgers
June 23, 2022
What .277 Fury Means For You, Means I need 1. When will i get an Ar10 .277 Fury from BCA ? I can get the ammo now without issue.
July 9, 2022
LOL, ridiculous. More of the $860 billion military spending (almost half of the US national budget) spent on "better" bang bangs and boom booms. Here's an idea. Rather than spending more money than the next 17 countries combined, why don't we just try using more diplomacy and helping other countries out of poverty and starvation and build a better world alliance? I know the lobbyist bought whores in DC are screaming NO!! and the CEO's and shareholders of Haliburton, Raytheon, General Dynamics, and Boeing are thrashing wildly on the floor over any suggestion of reducing MIC profits but, it's still We the People, right?
Dirk digler
July 16, 2022
You’re right about a lot of this with the exception of one thing…we don’t need to help any other countries we don’t need to fight other countries. We need to mind our own business and stop wasting taxpayer money.
October 7, 2023
Well the media and democrats destroyed the only president that shared that vision.
July 15, 2022
the energy comparison of 300win mag with a 180 grain bullet. for a short range hunting load is ok. but for launching a real bullet like the 225 bthp @a modest 2700 gets 2125 energy at 500 yards. would be a better match.
Billy Bob
July 17, 2022
HMMM... only reason I see they switched is because 6.8 x 51 will defeat body armor...
August 10, 2023
That was military's main request. To defeat current and proposed future armor at 500 yards.
Donald Underhill
July 27, 2022
It is my understanding that the .277 sig fury is a lower powered all brass case civilian version. It's what the military will use for training rounds. Firearms chambered in the .277 sig fury CANNOT withstand the pressures generated from a 6.8x51 military round
August 29, 2022
Incorrect. The 277 Fury is SAAMI spec'd for 80K psi, which is the same as the military rounds. Sig is currently selling a lower pressure FMJ all brass case practice round and a 80K psi hunting round for civilians on their website. Sig plans to apply the hybrid case technology to other cartridges as well.
August 10, 2023
I contacted Sig about that. All components of the Sig Cross are designed to the 80,000 psi criteria so the consumer can safely change Sig barrels as desired.
Barry Soetoro
August 8, 2022
BIG PICTURE PERSPECTIVE: 1. This contract was a slick deal between SIG and the DNC-controlled contract office at DoD. SIG is a New Hampshire-based, Blue-State industry, and is the highest DNC donor of all the DoD small arms manufacturers, and has been since it came to the US in the 1980's. 2. Notice that there are very few, if any, comparisons between the new SIG 6.8x51mm and the current 7.62x51mm NATO round. Why? Most all the 6.8x51 comparisons are against the 5.56 NATO or the old 308 hunting round. The reason for this is because the ballistics differences with the 7.62x51 NATO are so marginal that it raises profoundly disturbing questions. For instance, what is the wisdom of such an extreme expenditure for such marginal "improvement"? Sure, we need a more powerful infantry round, so let's equip our Soldiers and Marines with 7.62x51 rifles.....rifles that already exist in superb AR platforms. Given that the ballistics are so close, why do we want to create both a completely new round, AND two completely new firearms platforms? Why do we need to put all of our global allies into such a whip-lash logistics and manufacturing spin? The answer to these questions is very simple but also very costly: the DNC has rewarded their largest supporters with lucrative inside stock trading opportunities, while also enriching a true-blue DNC-supporting industry with yet another lucrative contract. 3. DoD does not want scrutiny of their decision to throw hundreds of billions of dollars into a completely different round and firearm system which will deliver marginal performance improvement at best.
October 23, 2023
October 30, 2023
August 9, 2022
with that high of chamber pressure things are bound to break. or at least wear out prematurely. its like the power of a long barrel 270 performance in a 13 in folder stock ar10. crazy. its definitely a game changer. it out classes even some med caliber long range guns like the 762x54r firearms. cant wait to get my hands on one.
Lou Barber
October 3, 2022
Very informative article & an exciting cartridge. I'm so glad that they are finally getting rid of a "varmint round" and giving our guys n gals something that they can defend themselves with.
December 12, 2023
There's no need for such an extreme round with so much recoil and weight. Simply shifting the AR-15 to a 6ARC or 6.5 Grendel would have gotten it done no problem, especially if the higher case pressure trick was used. I think they should have just gone all steel case instead of this silly bi-metal case for strength and cost. Most rounds in a fight are cover fire and aren't even aimed. This is why we went away from 7.62 in the 60s this is a step backwards. 6.8x51 isn't going to make an enemy any more dead than 6ARC or 6.5 Grendel would have. The soldier will have a heavier load out, less armo, he will be slower, more cumbersome, all the new snowflakes and women they are recruiting will not be able to handle working with a 5.56 firearm in combat much less this huge new gun. This is as horrible an idea as the P320 was vs the G19X, once again the Army is failing in plain sight.The corruption around this deal needs to be brought to light and all involved punished.
October 20, 2022
The M5/Vortex smart scope combo will only go to Combat Arms units. The majority of the Army will stay with 5.56 M4s. Ideally the M5 fielding will be supported with high fidelity ranges similar to the new Marine ranges. The Vortex smart scope (sort of son of Tracking Point) will be the real revolution. Traditionally the Army has done a lot of suppressive fire with relatively few hits. Watch the combat footage on YouTube. Many focus on the bullet, but only hits count.
December 12, 2023
Exactly the new optic with 6ARC or 6.5 Grendel from a new upper on M4s would have gone it done no problem, more than enough extra energy vs the 5.56 and similar long range ballistics to 7.62x51 especially is you used a 20" barrel which would be the same size as a longer action AR10 style upper with a 16" barrel. They are spend a bunch of money on the wrong places at the wrong time and it's pure corruption that is meant to benefit arm manufacturers not the soldier or the safety of the American people.
Walter R Jarboe
November 7, 2022
There already is a 6.5mm magnum. Recall, the .264 Winchester Magnum (ca. 1959), which develops 3,200 fps with a 140 gr .264 (6.5) bullet. There is also a .270 Win Short Mag that develops over 3200 fps with a 140 gr .277 (6.8) bullet.
November 19, 2022
Great article! I'd make one argument, and maybe I just missed it, when comparing 277 to the 6.5 Creedmoor. The Creedmoor only is comparable or even good when used in a 24" barrel. Fury on the other hand is designed to work in a 16" barrel. Makes guns shorter and lighter. I am not a bench rest shooter. I plink and I hunt in the Rockies. The idea of increased ballistics in a shorter and lighter package have me paying attention. A short time ago I was ready to buy a BN36X3 in 300winmag. This new round from sig made me put my purchase off, at least for a short while.
December 19, 2022
I prefer the 6.8 x 51mm designation. It's more informative than giving bullets stripper nicknames. You get a sense of what it is compared to the 7.62 x 51mm. And also answers alot of " is it the same as .." 80K psi, 16 inch , game changer.
Wiliam "Bill" Hicks
February 3, 2023
I'm a bit of a historian and can go back to my study of WWII when there was thought of chambering the venerable M-1 Garand in .270 Winchester. Ballistically, I'm of the belief that .270 Win would've been a better choice, but economic's may have been the incentive to choose .30-'06 due to the readily available supply from WWI surplus ammo supply. I grew up with my Father and Montana Grandfather and sat on their laps hearing about different hunting cartridges. I was always intrigued by .270 Win with its only deficiency being used against large or dangerous game. With that in mind, I believe there is much positive to say about the .277 Fury. The only caution I might make is that such a hot round may have a downside when it comes to wear on barrels and actions. As a Vietnam Vet., I even observed wear on barrels if the gun was used in full auto excessively.
John K.
February 8, 2023
The purpose of the 556 design is simple, weight. A soldier can carry more ammo, and still an effective cartridge for the grunt.
D. Lee Asher
March 2, 2023
Great article. For a similar historical tale check out the US Army development of the M1 garand and it's initial caliber of .276 Pedersen.
March 18, 2023
where is the BC upper for the 277 Fury? Already bought the ammo from Midway Sig Sauer Elite Performance Ammunition 277 Sig Fury 135 Grain Full Metal Jacket Box of 20!!!!
Sergeant 55
March 19, 2023
I want one!
May 18, 2023
so when do we expect to see a 277 upper from yall?
Everett Van De Voort
June 29, 2023
I would have thought that 7MM08 would have been a better choice. I've been shooting my AR10 in 7MM08 for 3 years now and it has performed perfectly on hogs.
Daniel OKelly
July 23, 2023
This nothing but hype. Glad you’re happy that Sig gave the cartridge a “cool name” so you’re not stuck referring to it’s NATO designation. BTW, has anyone else noticed that this is the same bullet as the .270 Winchester cartridge, except they increased its chamber pressure 18k psi to gain 50 fps in velocity?
Doug Good
August 1, 2023
United Steel Armory just came out with an AR 10 all titanium in 277 Fury! One badass rifle!
August 3, 2023
Just another case of Corporate buying the brass on another boon doggle. Fury is still a 308 base. It will be more expensive, not realistic for the guy who has to carry a rifle with 300 rounds into battle. Maybe it is better than a 308, so it can be a squad rifle or sniper rifle. Sorry, no magic here in my opinion.
October 6, 2023
Can't wait 'til the Army startmessing around with It. The 5.56 was a bad idea in the first place. Then the move from IMR to Ball C2 and subsequent to to replace the buffers. Then the shortening of the barrel to make carbine. Bingo! You had a 3200 fps rifle that is now down 2800 fps, same as the 7.62, but at one third of the bullet weight. The .M14 may have had some problems but it could punch through brush and medium trees. I never had any problem carrying 360 rounds (18 mags). You'd be suprised how little the ammo weighs when you get into a heavy firefight. People tending to drag a lot of crap on patrol they didn't need then bitched about the ammo weight.
Jon Gross
October 20, 2023
Great article! I've got nearly twenty AR's in 5.56, a couple in .308 and two in 6.5 CM. They're set up for anything you could imagine; CQB, Long Range, Hunting, Varmints, etc.... This new cartridge has me intrigued and I will follow developments closely. Thank you!
Algin Bishop
November 1, 2023
I started in the U.S. Army using the 7.62 x 51 MM (M14) and loved it. The M16 (5.56/5.7) has a purpose and has served fairly well (I served 36 years before retiring), but, other NATO countries tried to get the U.S. to go to their use of 25 caliber (6.5 mm) or the U.S. 270 (.278 caliber or 6.8 mm) instead of the smaller round. / Even though initial impressions is "going back to what works", the ballistics are very impressive and a move forward. / I am scratching my head as to why a two part/stage "brass" is being used, unless it is to be able to switch to an electric primer without having to change up the entire round. That will be something to find out. / I like it! I hope it goes into service sooner rather than later.
November 8, 2023
Right now sign sells standard rounds for standard prices, 130gr at 2700fps unknown bl. The premium is 150gr at 2800fps from bl 16. Sounds like a flexible big game package to me.
Tracy Martin
May 8, 2024
What does .308 minus .277 equal ??? .239??? really?
Frank Ferraro
May 14, 2024
Someone should check on whether any data has been compiled regarding the shelf life of this ammo due to the potential galvanic issues involving mating brass, stainless, and aluminum. On the surface, it seems like far too much complexity (and expense) for something that needs to be simple and reliable. Also other cartridges can reach 3000 FPS with the same or greater weight projectiles without reaching anywhere near 80.000 PSI.
Robert McIntosh
May 26, 2024
After several years of government trying to fit a real battle cartridge in a puny M4 they buy what amounts to a 308x51 necked down to the caliber it should have been, it should have been in use already. But 80,000 come on! Could have produced the 277 in house at say 65,000. One would think we're the going start shooting at 1,000 in the next war.
Stephen D Miller
May 28, 2024
Will you be manufacturing a Rifle in the new 277 Fury commercial or Higher Pressure 277 Fury round in the near future ?
Copyright © 2024 Bear Creek Arsenal, LLC. All Rights Reserved.