6.8 x 51mm / .277 Fury

[hkguns]

I couldn't find any threads on this, so here goes.

I picked this up on Saturday.

I bought the hybrid brass cases over a year ago and have been waiting for the rifle to hit the streets from SIG.

My Forster dies arrived today.

Quickload says I could possibly push 49-ish gr of H335, using 112gr bullets and be within pressure limits. Obviously I would work my way up to that number.

Reloading data is really hard to come by and I like to reference a few sources before loading some up and tossing them into the chamber.

Has anyone loaded for this cartridge yet? If so, what did you find and if you used QL can it be trusted like you would trust it with 30-06?

 

[hkguns]

Nobody? Not even a smart-@ss comment?

 

[ShootnFool8]

Just let us know, how it goes.

 

[spife7980]

If you have quickload then develop reasonable pressure loads and true the system to the real world.
Then push forward and see how high you can go without rising above the 80k psi.

With a steel case head the brass in the chamber is no longer the weak spot, the whole thing is equal so beware, it’ll go from nothing to a grenade when it does let loose from too much pressure.

I don’t know that anyone on here is doing anything with the hybrid cases that could share besides the one guy who can’t shut up about em. After reading his novels you’ll want to go back to regular brass.

 

[Doom]

I don't know about QL but I do use GRT and what would concern me about either is how well the powder models work going to 80KSI and also how the powers themselves behave. They may be fine but the issue is there is not much data available to qualify them.

As for the round itself I would be concerned about the primers, as we use these primes as indication we are over 65KSI. How will they hold up? Can we use them as an indicator of pressure? I doubt it. With the hybrid case the only pressure indication is hard bolt lift but in a Semi Auto that will be hard to detect.

It is interesting that no-one seems to have published data for 65KSI Fury. As for the 80KSI hybrid case this is a patented design and I suspect that only Sig is going to manufacture the case. At least for some time.

 

[hkguns]

Thanks for the responses.

With the rounds I normally load, I've found QL, to generally fall on the lighter side, as one would expect for safety reasons. I suppose I'll start with QL using a powder I have in stock that seems reasonable for the round. Which is exactly why I chose H335 in my original post.

Shooting for 65 - 70K in my first test rounds should be relatively safe. I'll just ensure I get a good H2O reading on the cases before and after firing.

Not sure me being the first one on here to try this cartridge is a good sign for its longevity.

I haven't seen the novels posted by the one guy who won't shut up about them. Unless he's the one forming them to another caliber. Time to do a better search.

 

[supercorndogs]

Didn't we see a custom action that sheared the lugs using 80k psi loads in alpha brass? Seems like the only thing that stopped it from lodging the boke in his face was the bolt handle hitting chassis.

Around that time didnt alpha put out a statement that their brass showed traditional pressure signs at much higher pressures?

Is running 80k psi in an action designed to run loads under 60k psi a good idea?

 

[hkguns]

Didn't we see a custom action that sheared the lugs using 80k psi loads in alpha brass? Seems like the only thing that stopped it from lodging the boke in his face was the bolt handle hitting chassis.

Around that time didnt alpha put out a statement that their brass showed traditional pressure signs at much higher pressures?

Is running 80k psi in an action designed to run loads under 60k psi a good idea?

Who exactly in this thread is talking about running 80K PSI loads in a 60K action?

 

[Supersubes]

Who exactly in this thread is talking about running 80K PSI loads in a 60K action?

Everyone who’s not shooting a Sig Spear is.

 

[Supersubes]

I don’t know that anyone on here is doing anything with the hybrid cases that could share besides the one guy who can’t shut up about em. After reading his novels you’ll want to go back to regular brass.

Well said.

 

[jbonnie]

At the risk of distracting from the primary purpose of the thread, does anyone happen to know if we can push the .277 fury through Sig’s NG762 suppressor? (Or any other 7.62 suppressor that folks are aware of?) FWIW the Huxwrx folks told me they would not put it through their 7.62 flow suppressors given the higher chamber pressure, which had surprised me not knowing anything about how these things actually work from an engineering standpoint since you can push a .300NM though there. Trying to figure out whether I need to wait for the Sig NG68 to become available or not….. Thanks in advance for any insights!

 

[Farmerbrown32]

Anybody have some load data for the 277 fury? Trying to figure out a good starting point with varget and 110 vmax

 

[Farmerbrown32]

I built a load with the 130grain ballistic tip this afternoon with varget powder and the hybrid case. Average 2900fps and shoots fantastic. Well under sub moa. Super impressed with the sig spear!

 

[XLR308]

Its kind of virgin territory and bucks the known norms but it's out there now.
Your going to get the usual nay layers and put downs regarding the operating pressures but the animal is out of the box so roll with it.
I personally have been contemplating a barrel for one of my kelbly actions in 277 Fury for a light weight hunting rig since it would be a real beast in a short action but I'm waiting to see more Comercial support for the round.

 

[Farmerbrown32]

Settled on the 145 eldx with varget. 2820 fps. Killed pdogs at 705,706 and 736 yards yesterday with it. Really splatters them well. Hope to find an antelope to get with it this weekend. Really happy with how clean the rifle stays even shooting suppressed. Super reliable and shoots very well.

 

[Chris Goodwin]

So this is my first post here, honestly just been doing a lot of reading. I do have an Sig Spear but impatiently bought one when they were just selling them in 7.62x51.

Due to my impatience with Sig releasing the Spear in 6.8x51 I decided to build a AR10. I used a x-caliber barrel, 4140 steel, 20 in, 5R, 1:7 twist, with a high pressure bolt and bolt carrier but it is still limited to 65k psi. I started out with the all brass casing box ammo, 135 gr FMJ and the 130 gr Venari SP. I took down all the necessary measurements, noting the 135 gr is using an extruded powder and the 130 gr hunting had a ball powder.

As you are finding there is no load data for this cartridge. Initially I based my load data on 7mm-08 as it’s a similar cartridge and case capacity. I am not using any programs just my experience handloading.

Down to business. I ran velocity and pressure tests using StaBall 65, H4350, and Reloader 16. H4350 just didn’t match the speed of Staball65 and Reloader 16 I have not completed a complete work up but in the 2850 fps range with low charges. I found a tight 1 to 1/2 MOA load with Staball65 at 49.6 gr and max is at 50.2 but still not seeing pressure signs or popping primers. At 49.6 I am at 2970fps with 130 gr Nosler Accubond. Just to mention fired case capacity averages 57.2 gr water with the all brass casing and the hybrid case.

I recently purchased 1000 hybrid casing from American Reloading. Deprimed and then resized with Forester dies. Following the same methods I did another velocity test working from 48.8 gr to 50.2 gr of StaBall 65 a 130 gr Sierra Gamekimg and the Hybrid case. Velocity ranged from 2882 fps to 2998 fps at 50.2 gr.

Right now I am working up a load for a 130 gr Barnes’s TTSX. All this for an amazing 1 shot kill on some fat wild boars here in Texas.

I just picked up an Sig Cross in 277 Fury and impressed with the 150 gr Accubond box ammo hitting 3000 fps with recoil feeling lighter than a .308 shooting the same grain bullet about 200 fps slower. At some point I hope Sig releases just the 6.8x51 upper, not looking to spend another $4k.
Sorry if this is long winded, just wanting to share. I am not chasing a 80kpsi threshold as some see as more important. My AR10 version has been extremely reliable, velocity is matching the hype of the round, and doing it safely.