pressure sign? *pics*

[Johnzor]

So this is my friends rifle its a Winchester 70 243. He says it never used to do this to his brass. He also mentioned his groups opened up to 5 inch groups at 200 yards where as before it was a solid 2 inches at 200. At first, we thought the rings were lose. Shorty after checking, I noticed his fired brass and seen the problem.
Please keep in mind its factory hornady match ammo, virgin brass, never reloaded.
There's a slight visual and I can feel it with my finger.
Its just above the datum line and can clearly see it in the pictures.
This happens after firing and kind of looks like a Dangerous problem.
Any feedback would be greatly appreciated as we are stumped.

http://s1112.photobucket.com/albums/k484...0911_151642.jpg

http://s1112.photobucket.com/albums/k484...0911_151655.jpg

 

[Gene Poole]

Re: pressure sign? *pics*

What do the primer/heads look like? That's the best indicator of pressure problems. As for that ring? I have no clue. I can't imagine what would do that other than a messed up chamber (somebody jammed the wrong go/no-go gage in it i.e.)

 

[former naval person]

Re: pressure sign? *pics*

Something left in the chamber? Try cleaning well for carbon and copper and then refire. If still there, get someone to scope the chamber.

 

[MALLARD]

Re: pressure sign? *pics*

section the case and lets look at the inside

 

[Johnzor]

Re: pressure sign? *pics*

Primer looks fine. No cratering or much flattened. I can see what your saying by jamming some wrong ex.no/go gauge. Although he doesn't own any..
I will section the brass and post pics when I get a minute.

 

[Fuzzball]

Re: pressure sign? *pics*

The chamber was cut with a reamer that had nick on the shoulder.

 

[Woodlanddude]

Re: pressure sign? *pics*

First, I would not shoot any more of that ammo starting yesterday. Second, get a light and look in that chamber. If nothing is seen, clean the shizzle out of the chamber area with an oversize brush with solvent, and then clean it out some more with oil and patches. Next, if all still looks good, try a box of something normal and mundane like wally world 100gr Rem or Win deer loads and look for the problem, to see if it is no longer there. Also the question of was he shooting HBN or molly comes to mind? Best of luck with it.

 

[former naval person]

Re: pressure sign? *pics*

Fuzzball...didn't he say it didn't happen with previous firings? That is why I wondered if new damage or crud has appeared. Could a larger diameter cleaning tip been jammed into the chamber?

 

[psubond]

Re: pressure sign? *pics*

something happened to his chamber. i support the clean it/scope it suggestion.

 

[jetsurgeon]

Re: pressure sign? *pics*

That doesn't look to good, I'd figure out whats going on before I shoot that stick anymore.

Best of luck,
J

 

[Fuzzball]

Re: pressure sign? *pics*

Fuzzball...<span style="font-style: italic">didn't he say it didn't happen with previous firings?</span>

That's a full circle ring, the only thing that can cause it is a defect in the chamber; If there's any kind of 'dirty chamber' problem it would not be so precisely consistant around the shoulder. The only way to produce that kind of chamber defect is the reamer it was cut with or jamming something like a "NO GO" headspace gage in it. And the case shoulder ring should be no more than a harmless cosmetic thing. All IMHO of course.

 

[MitchAlsup]

Re: pressure sign? *pics*

I agree with the "clean the crap out of the chamber" routine.

You might try a chamber brush with pelnty of solvent and some hand action.

 

[Joop]

Re: pressure sign? *pics*

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Fuzzball</div><div class="ubbcode-body">Fuzzball...<span style="font-style: italic">didn't he say it didn't happen with previous firings?</span>

That's a full circle ring, the only thing that can cause it is a defect in the chamber; If there's any kind of 'dirty chamber' problem it would not be so precisely consistant around the shoulder. The only way to produce that kind of chamber defect is the reamer it was cut with or jamming something like a "NO GO" headspace gage in it. And the case shoulder ring should be no more than a harmless cosmetic thing. All IMHO of course. </div></div>
I would agree with Fuzzball on this one. I would also want to see his cleaning method/equipment. If this just developed, I would think that it was created by some outside influence and not just a dirty chamber or bad ammo. I've shot plenty of rounds with chunks of crud/sand in the chamber and even in pitted chambers and it looked nothing like that. Much too uniform to be some kind of fouling, I would think.

ETA: the fact that the ring is coming OUT of the brass indicates that there has to be a ring dug INTO the chamber. It's not fouling.

 

[PCR]

Re: pressure sign? *pics*

"ETA: the fact that the ring is coming OUT of the brass indicates that there has to be a ring dug INTO the chamber. It's not fouling."

This has been my thought all along. Interested to see how this one comes out.

 

[Fuzzball]

Re: pressure sign? *pics*

A tiny metal chip caught on a reamer flute will easily do that to a chamber.

 

[PCR]

Re: pressure sign? *pics*

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Fuzzball</div><div class="ubbcode-body">A tiny metal chip caught on a reamer flute will easily do that to a chamber. </div></div>

Seen it before. Just below the shoulder, a half circle tear from dragging a chip. The brass looked just like the op's pictures.

 

[FLIGHT762]

Re: pressure sign? *pics*

Take the rifler to someone that has a Hawkeye type of bore scope and get it looked at and diagnosed. No easy answer here without looking at the cause.

 

[Aimsmall55]

Re: pressure sign? *pics*

I noticed in your first pic that the rim of the case head looks crooked. Almost like it wasnt properly held by the bolt face. Just a thought.