Reloading the 277 Fury 6.8x51 SIG Hybrid Case

[walk2112]

I heard last year the hybrid brass did this to chambers. It was only one sample, but now this is 4 or 5 occurrences I've observed. This obviously isn't the way. Imagine what it'd do in full auto form in military applications after 1-2k rds.

To me, that almost looks like gas cutting. Maybe pressure is getting out the steel/brass junction and etching thr chamber a bit each firing.

For science sake, do you know someone nearby with a saami 65cm reamer? Would be interested if you took the reamer and spin it in with a T handle, if any that deformation would disappear.

I was just about to chime in and say upon further inspection that looks like gas cutting to me too, gotta be what’s happening ya?

 

[Eric_F]

For science sake, do you know someone nearby with a saami 65cm reamer? Would be interested if you took the reamer and spin it in with a T handle, if any that deformation would disappear.

What's the idea behind this? I have a Go Gauge and it chambers fine. Sure, you could really ream it and set back the barrel, but I'm confused how you think this would help.

 

[khuber84]

What's the idea behind this? I have a Go Gauge and it chambers fine. Sure, you could really ream it and set back the barrel, but I'm confused how you think this would help.

Spinning a reamer in lightly by hand isn't gonna set a barrel back. Just wondering if the chamber deformation is all outward against and into the wall, or if some of its internal directed as well.

 

[Eric_F]

So the bolt closes on the Go Gauge, but with a bit more resistance than an empty chamber. Could indicate some deformation into the chamber space. Don't think I know anyone nearby with a reamer, unless there's someone local to the Twin Cities reading this thread that has one...

 

[khuber84]

So the bolt closes on the Go Gauge, but with a bit more resistance than an empty chamber. Could indicate some deformation into the chamber space. Don't think I know anyone nearby with a reamer, unless there's someone local to the Twin Cities reading this thread that has one...

Have any fired all brass cases from that rifle? Wonder if you chambered, closed bolt, and ejected if you'll see wear marks at the base the case.

 

[xsn10s]

Have any fired all brass cases from that rifle? Wonder if you chambered, closed bolt, and ejected if you'll see wear marks at the base the case.

I've seen the marks on my all-brass cases I fired. And I could catch my fingernail at the top of the band.

 

[Eric_F]

Have any fired all brass cases from that rifle? Wonder if you chambered, closed bolt, and ejected if you'll see wear marks at the base the case.

I haven't, but that would be interesting to try, but I think it's going to be just expanded out and eventually cause clickers from the chamber being too large

 

[HandgunHTR]

I was just about to chime in and say upon further inspection that looks like gas cutting to me too, gotta be what’s happening ya?

Based on how that case is designed, that is damn-near impossible. If gas is escaping there, the brass would separate.

My guess is that the steel portion of the case is springing back such that it is slightly oversized in the chamber. When it is chambered, it is actually "scraping" the chamber walls and pushing that metal forward, creating a ridge.

I have 174 rounds of this brass shot in my 7-08AI now. All but 40 of them were fire-forming loads. I did have a few of the pieces that were difficult to chamber when fireforming, but those cases were culled after firing as they were about 0.002" wider at the 0.200 line than the others. The remainder chambered easily and are all the same dimension as my Lapua brass before and after firing. I am not seeing a ring on my brass (I am firing a standard brass case after every 20 rounds fired), but I have also only shot 40 rounds that were "over pressure) so far. We shall see.

 

[Eric_F]

Based on how that case is designed, that is damn-near impossible. If gas is escaping there, the brass would separate.

My guess is that the steel portion of the case is springing back such that it is slightly oversized in the chamber. When it is chambered, it is actually "scraping" the chamber walls and pushing that metal forward, creating a ridge.

Agreed no way gas is coming out without case separation. The sharp steel ridge gouging is my theory too.

 

[xsn10s]

Yeah I agree the gas escaping was my first concern with these hybrid cases, and I saw nor smelled any evidence that gas was escaping.

 

[khuber84]

Well does anyone want to buy 190x brand new 277 fury hybrid cases?

 

[xsn10s]

Well does anyone want to buy 190x brand new 277 fury hybrid cases?

 

[waspocrew]

Well does anyone want to buy 190x brand new 277 fury hybrid cases?

Hahaha. I'll toss in 200 as well!

That etching is wild. I have a 22-250 AI barrel with about 800 rounds down the tube - I wonder how much work it'd take to use these fury cases in 22-250 AI. I wouldn't care about marking the chamber at this point in that barrel.

 

[walk2112]

Hahaha. I'll toss in 200 as well!

That etching is wild. I have a 22-250 AI barrel with about 800 rounds down the tube - I wonder how much work it'd take to use these fury cases in 22-250 AI. I wouldn't care about marking the chamber at this point in that barrel.

Haha I’ll toss in 500 here in about a week when they show up! I got excited with that sale… should have known they were on sale for a reason

 

[Nine Banger]

Haha I’ll toss in 500 here in about a week when they show up! I got excited with that sale… should have known they were on sale for a reason

I had 600 in my cart; bullets and dies in my midway cart; and my 308 take off barrel packed up and ready to send to be cut and threaded...

 

[longrangelead]

I had 600 in my cart; bullets and dies in my midway cart; and my 308 take off barrel packed up and ready to send to be cut and threaded...

don't be sceered. just part of the barrel usage.

 

[Eric_F]

I had 600 in my cart; bullets and dies in my midway cart; and my 308 take off barrel packed up and ready to send to be cut and threaded...

On the topic of hybrid 308, American Reloading did sell one lot of some Sig hybrid cases which sold out immediately. I got a couple of them sent to me accidentally in my 277 orders.

 

[Eric_F]

don't be sceered. just part of the barrel usage.

I'm inclined toward this thought, I've got two cheap Tikka Lite takeoff barrels I wouldn't mind at all using with hybrid loads for some low-volume, high velocity hunting loads. Tons of rifles taken out only for deer season never get to 250 rds, though much less so on this forum.

Unfortunately, I wanted to use these cases in a higher volume NRL Hunter and PRS (Sportsman division) rifle. So now I'm paring down my brass supply, and need to figure out how bad my CTR barrel is. I'm going to get some soft (Hornady?) and hard (Alpha) brass and seeing how bad the case head expansion gets after a few firings.

 

[Nine Banger]

Y'all think if I nitride my take off barrel it will still "do it"?

 

[HandgunHTR]

Y'all think if I nitride my take off barrel it will still "do it"?

I think it depends on what the mechanism for the issue is. If it is "scraping" like I mentioned above, then nitriding should eliminate it. If it "hammer forging" as has been postulated, then nitriding wouldn't help as the cases would still push the chamber material outward with each firing. Nitriding only goes a few thousandths deep.

@Eric_F, are you able to take some Scotch-Brite and do a quick "polish" on that and then take another picture? Scotch-Brite shouldn't remove any material, but it should polish it up a bit to get a little more definition. Also, is that transition a bump or a groove?