HinAll, the 6.8x51 / .277 Fury has been out there a year now. I'm curious if anyone has seen commercial or semi-commercial AR-10 platform barrels out there that can handle the high 80kpsi pressure yet. I've heard there is a proprietary metallurgy to the gov barrels so not sure if any experimenters out there have made something close yet. I have seen some SS barrels but they are limited to 68Kpsi
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.277 Fury Barrels
- Thread starter scottneh
- Start date
I don’t think many, or any, manufactures are going to support the .277 Fury in the AR-10 platform. Why would they given the increased liability? There might be bolt heads and extensions out there that can handle the pressure, but it sounds like a lose-lose proposition for companies to offer a barrel on a platform it was never designed for.
edited to add - handling the pressure for a dozen or even a couple of hundred rounds doesn’t mean it’s safe over a lifetime.
edited to add - handling the pressure for a dozen or even a couple of hundred rounds doesn’t mean it’s safe over a lifetime.
There’s a recent interview with SIG where they said they backed down on the pressure because it was causing issues with early accuracy loss. I believe they said that 70,000psi was more of a sweet spot for that.
They said barrel life was determined by accuracy and velocity losses outside of a certain range, and threw out a rough 4000rds barrel life given their performance thresholds.
In other words, you can match the downrange performance with a 7mm SAW or 7mm-08 Improved, without chasing high chamber pressures.
They said barrel life was determined by accuracy and velocity losses outside of a certain range, and threw out a rough 4000rds barrel life given their performance thresholds.
In other words, you can match the downrange performance with a 7mm SAW or 7mm-08 Improved, without chasing high chamber pressures.
I had some interest so I googled it and came up with this:
moriartiarmaments.com
After reading some of the SHTF threads on the hide I decided not to spend the money on a new caliber, but to get more ammo for what I have. Sticking to 5.56 and 7.62x51; with some 7.62x39 and 6.5 creedmoor.
AR-10 .277 Sig Fury Hybrid - The New Caliber of 2023
The AR-10 is one of the most reliable and versatile firearms in existence. And with the recent release of the .277 SIG Fury Hybrid, it has only gotten better.
moriartiarmaments.com
After reading some of the SHTF threads on the hide I decided not to spend the money on a new caliber, but to get more ammo for what I have. Sticking to 5.56 and 7.62x51; with some 7.62x39 and 6.5 creedmoor.
Sig is apparently releasing the Spear (not the limited edition version that was released a while back) in .277 and there will be a new Cross in .277 as well, within the year (from Sig's own mouth, see vid below). Pressure has been lowered to 70,000psi and the Cross barrels are being nitrided to prevent premature wear. I guess it's fairly accelerated on a straight up untreated stainless barrel.
Accuracy and lifespan were the reasons for lowering the pressure.
Accuracy and lifespan were the reasons for lowering the pressure.
You can just click on video, I started it at that time stamp so you do not have to watch the prior 17 minutes of a talking head.
Here:
and here:
BRAND NEW CBC INDUSTRIES 277 FURY AR 10 BARRELS!
BRAND NEW BARRELS CHAMBERED IN .277 FURY FOR AR 10S!! FIRST OF ITS KIND! CBC INDUSTRIES 16" SPIRAL CUT STEEL WITH 1:7 TWIST! BULK DISCOUNTS. These are rated for standard loads not high pressure! These barrels have been sent to me from an AR10 Manufacturer on consignment. I know nothing about the...
www.ragindutchmanblades.com
and here:
Yes, I read they lowered the pressure to around 70,000 psi for better accuracy and barrel life. They are being used in full auto military weapons.
But the high pressure loading isn't dead.
Interesting video from the Ultimate Reloader, "308 W 300 WM velocities do not do this at home." Check out this video, where their two companies reps running the 308W to over 100,000 psi.
Do Not Do it...really. but they used a BAT action and new Alpha brass.
And for those interested with common sense and good reloading skills one can use the 6.8 X 51 hybrid brass for the 308, 6.5 CM, 8.6 Blackout, 358 Win and improve the velocity of any cartridge based on the 308 case head with shorter or similar COAL. And ya don't need 80,000 psi for an improvement. But neck turning and annealing are needed.
But the high pressure loading isn't dead.
Interesting video from the Ultimate Reloader, "308 W 300 WM velocities do not do this at home." Check out this video, where their two companies reps running the 308W to over 100,000 psi.
Do Not Do it...really. but they used a BAT action and new Alpha brass.
And for those interested with common sense and good reloading skills one can use the 6.8 X 51 hybrid brass for the 308, 6.5 CM, 8.6 Blackout, 358 Win and improve the velocity of any cartridge based on the 308 case head with shorter or similar COAL. And ya don't need 80,000 psi for an improvement. But neck turning and annealing are needed.
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Currently running a x-caliber barrel. https://www.x-caliber.net/ar-10
I chose 4140, 20 in SOCOM Bull barrel, 5R, 1:7 twist. I wish it was better but seeing 1/2 to 1 MOA accuracy. Also using their high pressure bolt.
I chose 4140, 20 in SOCOM Bull barrel, 5R, 1:7 twist. I wish it was better but seeing 1/2 to 1 MOA accuracy. Also using their high pressure bolt.
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Remember this is a 65,000 max pressure
.277 Fury, as stated by the manufacturer, not the 6.8 X 51 80,000 psi platform.
I run magnum pressures 62 to 65,000 psi in AR 10s with cartridges like 338 RCM.
But leave the 80,000 psi and hybrid cases to stout bolt guns.
Well one factor no one knows is what powder Sig is loading the factory hybrid cases with. I can tell you the the factory load 135gr FMJ all brass case ammo is loaded very hot for a DI gun/my AR10 and shot in my cross was about 150 fps slower. In my AR10 on a warm day it would pop primers and ruin the casing some of the time.
I would consider in my loads that the hybrid casing is really just over engineered. StaBall 65 is not showing any pressure signs in all brass casings and of course you can not tell with the hybrid cases other than primer signs. Case capacity is identical and primers I suspect are CCI 34 or similar. The hybrid case alone is not making the load high pressure, just able to withstand a hotter load. More than likely a faster burning powder to achieve the velocity and increased pressure for at 13 in barrel to achieve 3000 fps. This isn’t .223 to 5.56 or .308 to 7.62x51 difference in pressure where case wall thickness lowers or increases capacity for higher pressures. We are all guessing at this point and I do not have Quickload or any other program to simulate pressure numbers. If someone would like to run the simulation for me in Quickload using Staball65 that would be interesting.
Again I am not chasing 80,000 psi I have no device to measure it and not dumb enough to shoot the factory load hybrid ammo. I am just using the hybrid case to duplicate the safe loads I have developed with the all brass case.
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