Anyone tried 6.8X51/.277 Fury hybrid cases?

[Bodhisafa]

What if pressures are kept low around 62,000 psi, would these cases still cause issues?

 

[DaveTooley]

Just my opinion.
The steel section extends past the solid part of the case head. It gets thinner as it gets to the transition with the brass body. I think, even at normal pressures, that area will eventually expand just like an all brass case. Of course we're going to try and make it work in our world but it was designed to be one and done.

 

[Bodhisafa]

I am building an AR 10 for hog hunting. I was going to use this cartridge but if the brass is an issue I will need to change tracks.

What cartridge would be equivalent that would be great in an AR 10? Besides 308/6.5 creed.

 

[DaveTooley]

I am building an AR 10 for hog hunting. I was going to use this cartridge but if the brass is an issue I will need to change tracks.

What cartridge would be equivalent that would be great in an AR 10? Besides 308/6.5 creed.

If you want knock down power go 338 Federal.

 

[SKWERLZ]

I’m curious what they are doing for extractor materials and heat treatment with these steel base cases.
It’s gotta be rough on extractors designed around conventional cases.

 

[DaveTooley]

I’m curious what they are doing for extractor materials and heat treatment with these steel base cases.
It’s gotta be rough on extractors designed around conventional cases.

My guess is on the initial firing extraction isn't bad, or worse than anything else. Even with steel there will be some spring back. Now if you exceed the strength of the chamber walls and get some expansion there then all bets are off.

 

[SKWERLZ]

My guess is on the initial firing extraction isn't bad, or worse than anything else. Even with steel there will be some spring back. Now if you exceed the strength of the chamber walls and get some expansion there then all bets are off.

Was thinking of it snapping over the steel rim repeatedly instead of a brass rim, maybe a moot issue but certainly could get interesting.

 

[DaveTooley]

Was thinking of it snapping over the steel rim repeatedly instead of a brass rim, maybe a moot issue but certainly could get interesting.

They have thought of that.

 

[Griffbl]

To add what Walt is saying….

The steel case head will start to ring the chamber after X amount of rounds at high pressure. I’d give you about 250-500 rounds and you will start to have extraction issues. Serious issues.

Also running it at high pressure on standard bolt guns… be prepared to use a dead blow hammer to open the bolt not just on the uplift but beating it back as well.

Also copper fouling will be an issue and effecting accuracy. To hold good accuracy you will be cleaning it about every 30 rounds.

Walt can correct me if I’m wrong but if I am… I’m not far off.

I have to agree with Walt… right now for the intended purposes of a military round with purpose built guns for that round is where it’s at and not for casual or target shooting in conventional guns.

Later, Frank
Bartlein Barrels

Frank-

I would like your opinion as to this: I will take it a s a given that the hybrid case junction of steel and brass is obviously "ringing" chambers at some point...Question for you Sir: Do you think Federal's approach (i.e. 7mm Backcountry) with an all steel case is a better solution for higher pressures than is the Hybrid case employed by Sig? Thank you so much. I appreciate your posts and inputs given your expertise.

Most Sincerely,
Brad Griffith aka Griffbl

 

[DaveTooley]

Frank-

I would like your opinion as to this: I will take it a s a given that the hybrid case junction of steel and brass is obviously "ringing" chambers at some point...Question for you Sir: Do you think Federal's approach (i.e. 7mm Backcountry) with an all steel case is a better solution for higher pressures than is the Hybrid case employed by Sig? Thank you so much. I appreciate your posts and inputs given your expertise.

Most Sincerely,
Brad Griffith aka Griffbl

Only time will tell.

 

[Straightshooter1]

Tried some H-4895 last month:

177 SMK's
45.5 grs H-4895
Case Fill: 95%
COAL: 2.977
Case Volume: 56.3 gr H2O *
Ambient Temperature: 93°F
AVG MV: 2,876 fps
Barrel: 26" 10:1 Krieger Heavy
SD: 7.1, ES: 23
QL Estimated Pmax pressure: 79,050 psi

Again, all cases extracted normally with no bolt lift issue and no pressure signs of any kind. While they all fired well and the results on target were decent (10 shots fired), this is more pressure than I need or want. But was an interesting test for this powder.

*Case head stamp on this one was "24", having less case volume than the previous I posted here.

 

[EricF]

From 233 rounds of hybrid SIG cases resized to 6.5 Creed. Weren't loaded super hot, most were 44 gr H4350 with 140 ELDs, about 2750 fps in a 20" CTR.

 

[Walt Krafft]

Yup. There it is.

 

[CJ6]

It's like nobody listens when somebody that helped develop the cartridge tells what's going to happen.