Chamber grooves caused by .277 Fury

[TackDriver284]

I got word from a fella who posted a report concerning his gas gun. He converted 6.8 x 51 / 277 Fury hybrid cases to a 6.5 Creedmoor and experiencing grooves cut into his chamber by those .277 steel cases. His report:

"I had to eat a slice of humble pie today. For those of you following my process of converting 6.8x51/277 Fury hybrid cases into 6.5CM. I finished cleaning the barrel on my PRS Open rig and put in the borescope to check the carbon ring. While looking at the chamber wall, I found this groove cut in it right where the brass and steel pieces meet on the hybrid cases. After test firing a couple standard brass case loads, I found that I now even have standard ammo sticking.
Luckily, this barrel isn't completely toast. Its a 1.25" straight contour, 28" long. That means I can get it cut back about 2" on the chamber end and rechambered. For now while I wait for my turn in the queue at Hickory Hill Arms (sorry for screwing up a damn good barrel Wes), I'll be running my spare 6.5 PROOF Research prefit.
Oh, and I made a new set of weights for my 6.5 gas gun, got tired of moving my 1 set of weights between two rifles."

No further details on this,,,is anyone getting issues concerning grooves being cut into your chambers using .277 Fury cases?
Not bashing those who have 277 Fury. Just a concern that there are reports on the internet concerning groove issues using 277 Fury Hybrid cases.

 

[Yoteklr]

I've been shooting 277 Fury in a Stick Shift rilfe for about 300 rounds. I have definitely hotrod my loads somewhat.
My borescope shows a line in the chamber. However I haven't had any extraction issues.
This is a large shank savage action. The barrel shank and threads have a bigger diameter than a Small shank. I'm not sure if that helps but I will say that savage doesn't have the best extractor available and I still don't have extraction issues.
I formed 100 cases to 308 winchester for a Ruger SFAR. I stopped shooting them in this rifle because I was afraid to dull or break my extractor on the SFAR because they are $50 instead of $20 for a regular ar10 extractor.

 

[TEXASforLIFE]

I downloaded to 65k as the barrel/bcg/extension isn't 80k rated. I have an AR in 277fury, but haven't had time to finish the build along with the other AR's from 4 years ago. I think on LRH there's a thread about the hybrid cases as some neck to different calibers to meet their wants. Might get answers there?

 

[BiggerHammer]

Well, that makes me want to rethink one of my rifles projects. I have a bunch of the bimetal .277 Fury brass. I may get rid of this stuff. I was going to neck it to 6mm in a 7 twist with the new 120gr A-Tips and see how quick I could shoot out a barrel. It probably wouldn’t take long but it would be FAST and FUN while it lasted.

 

[TEXASforLIFE]

From reading about this brass some thought there was agas leak where the 2 are joined and others had some kind of ring in the throat at neck. IIRC all have been tested in a BA and not in semi's?

 

[IdahoCTD]

The different expansion rates of steel and brass could explain the gas leakage. I said it before but.....steel cases dont give like brass and any little spec of dirt can cause scratching. Also 80kpsi will show issues not otherwise seen at 65kpsi. If I was going to try 80kpsi I'd nitride the barrel to make it harder then the brass but truth be told is a waste of energy. Everyone is trying for the next best thing but 80kpsi isnt it. It stresses everything.

 

[TEXASforLIFE]

The different expansion rates of steel and brass could explain the gas leakage. I said it before but.....steel cases dont give like brass and any little spec of dirt can cause scratching. Also 80kpsi will show issues not otherwise seen at 65kpsi. If I was going to try 80kpsi I'd nitride the barrel to make it harder then the brass but truth be told is a waste of energy. Everyone is trying for the next best thing but 80kpsi isnt it. It stresses everything.

80k will sell more parts. 65k is enough

 

[jimbires]

The different expansion rates of steel and brass could explain the gas leakage. I said it before but.....steel cases dont give like brass and any little spec of dirt can cause scratching. Also 80kpsi will show issues not otherwise seen at 65kpsi. If I was going to try 80kpsi I'd nitride the barrel to make it harder then the brass but truth be told is a waste of energy. Everyone is trying for the next best thing but 80kpsi isnt it. It stresses everything.

I have to wonder about making the barrel harder too . at what point does a hardened barrel split because it can't expand . 80KPSI will bring out the weak links , in this chain .

 

[phil]

This new method of higher velocity appears to have some side effects. I guess I’ll be sticking to longer barrels and generous cases.

 

[IdahoCTD]

I have to wonder about making the barrel harder too . at what point does a hardened barrel split because it can't expand . 80KPSI will bring out the weak links , in this chain .

Nitriding is a very thin surface treatment so I wouldnt sweat it for cracking, not to mention the highest pressure is encased mostly by the action and the largest diameter of the barrel. If it was through hardened then it would be prone to potential cracking. The point I was making is these steel cases have little to no give compared to brass and will cause problems in the chamber unless the barrel is addressed too.

 

[TEXASforLIFE]

When some barrels are proofed to 100k+ you just need to know what you're getting. Chamber will be the thickest part so mo worries there? I haven't seen the sig cross design or others that produce firearms for 80k usage, but have seen the bolt and extension design on the 277fury AR. There's a notable difference between 65 and 80k design. It's not like there's more powder in yhe case for the velocities just faster burning to achieve those.