Case head separation causing "nick" in chamber wall

[bsumoba]

Alex, I decided to leave it. I simply removed the carbon and copper. The nick is very shallow so I don't forsee it being an issue.

I am/was trying to extend the brass life. Brass is Lapua. I am quite pleased with the amount of life I got out of the brass. It really is time to retire the brass as I am very confident that the case head separation was due to the volume of firing the case had on it. I didn't keep track of how many times each case was fired. It could have been that this particular case was fired MANY more times than the rest.

All other rounds fired just fine and were sized at the same time so it wasn't excessive headspace. I have done that before in my tactical rifle and scrapped about 80 pieces of brass. That incident was about 0.008-0.010 of shoulder bump, which resulted in case head separation. I normall bump my shoulders 0.002".

I am usually good with identifying case splits, I cull out loose primer pockets and also try to inspect for signs of incipient case head separation. Nothing really shouted out at me at the time I was doing brass prep. I don't do the paper clip method. I usually try to look for faint lines just above the case head. This was the first case out of about 300 cases in circulation that has done this. I am just glad it wasn't worse.

 

[Terry_M]

Ehh, I would guess that many others have had case head separation for the same reason. I know I have in two different rifles. It's hard to change components when you get a good performing load. You just don't know what the next batch will do and it is so hard to take that chance once you finally get things clicking so well.

I really don't think you were in any danger and you're not exactly a novice.

 

[JohnKielly]

284 used a rebated bolt face looks like the the case the extractor groove was cut too deep

Can't be. The nick is in the chambered area of the barrel.

 

[DOGCAPPER]

From a casual look at the picture I would say the chamber cut is sloppy and the spot in question was done during the chamber cut and filled in with fouling from shooting.

 

[rardoin]

I know Devcon can replace scope ring uppers......just putting that out there.....

 

[/VH]

I know Devcon can replace scope ring uppers......just putting that out there.....

I guess great minds do think alike! I actually did fill the pit in the S&W firing pin bushing with JB Weld, a couple times. It kinda almost worked but I couldn't get it to stay in there.

 

[rardoin]

I know Devcon can replace scope ring uppers......just putting that out there.....

Edit....of course I am in jest.

 

[XBBR Shooter]

OP says he had many firing on this brass "experienced brass" and brass flows toward the case mouth as it is fired. Over time all brass will fail, usually just above the web or in the case neck. It's just unfortunate in this instance that something was propelled sideways into his chamber hard enough to score it and leave a permanent mark. Not all case head separation is caused by improper head space. Yes by running a dental pick or some other small sensitive wire into the case you can feel when the case gets a rough or textured section just above the web. That does not mean instant failure, and if you're being frugile you can push those cases for additional firings. Question is how many more....

"... and brass flows toward the case mouth as it is fired."

Brass does not flow forward when the case is fired. The stretching is caused when cases are shorter than the chamber (by over sizing with an FL die). When the case is fired, it moves forward to fill up the excess space - then the case walls stick to the chamber, and the head gets pushed BACKWARD until it hits the bolt face. And it stretches just in front of the web... if you over size the case again, the problem continues and soon, the head falls off of the case body.

"Over time all brass will fail."

I don't know what your definition of "over time" (how much time?) But I have gotten 45 loadings out of Winchester 22-250 cases, without a failure, and many people have gotten 80 to 100-ish firings.

Head separations are NOT inevitable.

 

[22BRGUY]

"... and brass flows toward the case mouth as it is fired."

Brass does not flow forward when the case is fired. The stretching is caused when cases are shorter than the chamber (by over sizing with an FL die). When the case is fired, it moves forward to fill up the excess space - then the case walls stick to the chamber, and the head gets pushed BACKWARD until it hits the bolt face. And it stretches just in front of the web... if you over size the case again, the problem continues and soon, the head falls off of the case body.

"Over time all all brass will fail."

I don't know what your definition of "over time" (how much time?) But I have gotten 45 loadings out of Winchester 22-250 cases, without a failure, and many people have gotten 80 to 100-ish firings.

Head separations are NOT inevitable.

How often do you anneal if I may ask?

 

[bsumoba]

From a casual look at the picture I would say the chamber cut is sloppy and the spot in question was done during the chamber cut and filled in with fouling from shooting.

negative. chamber was cut fine. fouling normally does not travel down that far on the case when firing in a bolt action. Carbon fouling is usually only found on the neck and maybe into the neck/shoulder junction.

How often do you anneal if I may ask?

every 1-2 firings. 3 if I am really lazy.

 

[/VH]

Edit....of course I am in jest.

...and of course, I did have the bushing replaced.

 

[22BRGUY]

negative. chamber was cut fine. fouling normally does not travel down that far on the case when firing in a bolt action. Carbon fouling is usually only found on the neck and maybe into the neck/shoulder junction.




every 1-2 firings. 3 if I am really lazy.

Thanks
I think that's an important key with Winchester brass right from the get go....and any brass over time, although Lapua brass comes well annealed in my experience.

 

[XBBR Shooter]

How often do you anneal if I may ask?

between every firing for benchgrade rifles, to every 3 to 5 firings for others.

 

[msinc]

I had a similar occurrence with my 280AI...except the mark I had was a little bit worse than yours. I shouldered back and rechambered, but if it was barely marking the brass I would have let it go. Mine actually caused a bolt click and a little harder extraction.

 

[bsumoba]

*** UPDATE ***

Just an update, as mentioned, I cleaned up all the brass and carbon from the chamber wall as best as I could. I went to shoot the gun. Same load, same everything.

NO issues whatsoever. There is only a real slight marking on the case, but it is hardly noticeable and you cannot feel it unless you really try.

After about 5 rounds of fouling from a clean barrel, gun went back to shooting what it normally shoots. Again, this is a 284 Shehane, 56.3gr H4831SC. 10K off the lands (.235 FB), 180 hybrids. Going about 2880-2890 fps in a 30" brux barrel.

4 shot group at 100 yards.

 

[22BRGUY]

*** UPDATE ***

Just an update, as mentioned, I cleaned up all the brass and carbon from the chamber wall as best as I could. I went to shoot the gun. Same load, same everything.

NO issues whatsoever. There is only a real slight marking on the case, but it is hardly noticeable and you cannot feel it unless you really try.

After about 5 rounds of fouling from a clean barrel, gun went back to shooting what it normally shoots. Again, this is a 284 Shehane, 56.3gr H4831SC. 10K off the lands (.235 FB), 180 hybrids. Going about 2880-2890 fps in a 30" brux barrel.

4 shot group at 100 yards.

Great to hear!

 

[rardoin]

*** UPDATE ***

Just an update, as mentioned, I cleaned up all the brass and carbon from the chamber wall as best as I could. I went to shoot the gun. Same load, same everything.

NO issues whatsoever. There is only a real slight marking on the case, but it is hardly noticeable and you cannot feel it unless you really try.

After about 5 rounds of fouling from a clean barrel, gun went back to shooting what it normally shoots. Again, this is a 284 Shehane, 56.3gr H4831SC. 10K off the lands (.235 FB), 180 hybrids. Going about 2880-2890 fps in a 30" brux barrel.

4 shot group at 100 yards.

I would set it back and rechamber it...you might then tighten up the groups a bit!