Split case

[cape cove]

Here's my measurements
New- web = .465, mid body = .454, shoulder = .452
Fired- web = .472, mid body = .460, shoulder = .455
This seems quite a bit oversize to me but I am not sure. If this is excessive then I am definitely over working it.
The rifle shoots well and is only used for hunting so if I can only get 4 or 5 loads on a piece of brass I am ok with that.

Now take a fired case and resize it and post the measurements at the same spots. JMO

 

[birddog 68]

I didn't notice this morning when you sent photo but is that the normal full length size ring near base or separation ring ? I think sizing ring but wondering.

You are thinking correctly, full length size ring.

 

[arch408]

My theory is a bad case. Unless this a new gun, that problem would have showed up sooner. I would first make sure the chamber was good. Easiest way would be to rotate a fired case on rollers and measure any inconsistency with a test indicator. that will show any case bulges. Inspect fired cases for bright lines. They could indicate brass stretching and thinning. You can also check stretching by putting a ninety degree bend in a wire. Sharpen to make a point. Insert the wire into the case and move it around both directions. If the brass is stretching the wire will catch that area. If all the fired cases don't show any stretching, I would call the rupture a single anomaly. If other cases show stretching, I would investigate further. Compare new and fired case measurements to see how much the cases are expanding after firing.

 

[arch408]

Oops, didn't see previous two posts.

 

[birddog 68]

Oops, didn't see previous two posts.

No problem. Good information. Thanks

 

[birddog 68]

Now take a fired case and resize it and post the measurements at the same spots. JMO

I had some sized already.
Sized - web = .468, mid body = .457, shoulder = .452

 

[Mikecr]

In my opinion ~7 thou chamber clearance is excessive.
Your brass is yielding a huge amount, weakening it. You can smash it all back down with a FL die, but that's just a terrible thing to do to brass.

 

[WYO300RUM]

You are thinking correctly, full length size ring.

Thanks !

 

[MagnumManiac]

I agree, .007" is excessive.
I have a 25-06 that is zero on head space, but, in the body and the web, it grows .008". I know this and expect brass not to last, but, surprisingly, using re-formed Lapua brass, it hasn't split a case yet.
The expansion line is very noticeably larger, I don't see that on your brass.

Cheers.

 

[jseandsje]

How did you anneal?

Are all of your cases experiencing .007 web expansion after firing?

 

[birddog 68]

How did you anneal?

Are all of your cases experiencing .007 web expansion after firing?

@K.E.C. Darkside annealed them for me and not sure which machine he has but this split is way below that.
I measured 4 fired cases and they were all .006-.007

 

[jseandsje]

@K.E.C. Darkside annealed them for me and not sure which machine he has but this split is way below that.
I measured 4 fired cases and they were all .006-.007

That seems a lot for the web. And you are reducing the web after full length resizing.

I have read anything above 0.0015 is asking for trouble.

If your chamber is causing this you might have to neck size and shoulder bump and leave the body alone.

 

[birddog 68]

I'm guessing that I have 3 options
1: neck size and shoulder bump only.
I'm assuming that I will need to size the body eventually for proper feeding?
2: order a custom full length sizing die
The couple that I looked at were 2/3 of what I paid for the rifle.
3: continue as I have only discarding brass after 3rd firing and carefully inspecting between loading.
I am probably going to rule out #2 unless there's a cheaper alternative.
Any options that I have overlooked?
Once again this is a hunting rifle that only gets 50 rounds shot a year.

 

[cape cove]

This may only be a bad batch of brass as other posters have alluded to. Get some new brass, maybe a different brand and see how things go before spending money that may not need to be spent. JMO