Case separation on first firing

propliner said:
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It looks like it's headspacing on the belt ok.
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That appears to be fine as far as excessive headspace is concerned. I can't see this causing separation at the first firing.

Until headspace is checked with a steel no go gauge I am sticking with a batch of faulty brass as the problem.
 
For those unfamiliar with the Blaser R8 bolt lug system, it locks radially with 14 lugs.
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The bolt carrier also has a couple of rear lugs that move down for added safety if the front lugs should fail.
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guntech said:
That appears to be fine as far as excessive headspace is concerned. I can't see this causing separation at the first firing.

Until headspace is checked with a steel no go gauge I am sticking with a batch of faulty brass as the problem.
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I did try two different factory Weatherby loads but who knows?... maybe they got the same brass.
 
Update:

I compared the aftermarket barrel to a Blaser barrel.

After inserting the bolt and locking the action (sans receiver) into each barrel, the bolt head in the Blaser barrel has no discernable forward/rearward slop. The problem barrel has .029" of slop.

This seems like a huge discrepancy.
I believe the machining of the recessed locking ring is too wide and the stop face ot that ring is too far rearward in the barrel, allowing for excess movement of the bolt head.

It would be like the bearing face of a standard bolt action's lugs being machined .029" too far rearward. However, on a straight pull action like this you don't feel the lack of tightness.
 
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I am not familiar with the Blaser R8... but the 29 thou of slop between the two barrels may be the problem.
 
The only time I’ve had new brass separate halfway up the case on the first firing was with a batch of Remington 222 Rem mag brass that was new in the bag. Who knows how old the brass was or if it was just a batch of brittle brass to start with.
 
Propliner, thanx for the extra information and excellent pics. You likely have found the cause of your problem. Now, will the barrel maker do the right thing and replace it???? Usually, they bend over backwards to fix such a screw up.
 
bearhunter said:
Propliner, thanx for the extra information and excellent pics. You likely have found the cause of your problem. Now, will the barrel maker do the right thing and replace it???? Usually, they bend over backwards to fix such a screw up.
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A second email has been sent with my findings. The first email has gone unanswered. I've read that this builder doesn't have stellar service when it comes to defects.
 
Update:

The go/no-go gauges showed up.

The go is no problem. The no-go failed. I could close the bolt with 3 layers of Scotch tape on the back of the gauge, so .006" over the no-go.
 
propliner said:
Update:

The go/no-go gauges showed up.

The go is no problem. The no-go failed. I could close the bolt with 3 layers of Scotch tape on the back of the gauge, so .006" over the no-go.
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A big failure in fitting and chambering the barrel... I sure hope you get your money back. I don't know if I would want him to supply a replacement.
 
guntech said:
A big failure in fitting and chambering the barrel... I sure hope you get your money back. I don't know if I would want him to supply a replacement.
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The problem is that I have a bunch of accessories that go with it, and are useless on most anything else.
 
All may not be lost yet. Necking 300 weatherby brass necks down just enough for a false shoulder crush fit would get some use out of the barrel
 
JJ-65 said:
All may not be lost yet. Necking 300 weatherby brass necks down just enough for a false shoulder crush fit would get some use out of the barrel
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I've actually thought of that today too. But I think since it's chambering ok on the belt that the excess space behind it would stretch the case in front of the belt anyways.

I've read that a belted case can stretch two ways... from the belt forward and from the belt back, too.
 
With the case head heir firmly against the bolt face before firing, there shouldn’t be any case stretching until you exceed 65.000 psi. The shoulder will be blown out forward to fill the empty space in the chamber but the overall length of the newly fired case won’t grow in length and it may actually shorten a bit.
 
JJ-65 said:
With the case head heir firmly against the bolt face before firing, there shouldn’t be any case stretching until you exceed 65.000 psi. The shoulder will be blown out forward to fill the empty space in the chamber but the overall length of the newly fired case won’t grow in length and it may actually shorten a bit.
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The proper way to fire form.
 
JJ-65 said:
With the case head heir firmly against the bolt face before firing, there shouldn’t be any case stretching until you exceed 65.000 psi. The shoulder will be blown out forward to fill the empty space in the chamber but the overall length of the newly fired case won’t grow in length and it may actually shorten a bit.
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I guess in this instance, the belt becomes more or less irrelevant.
 
Tokay444 said:
The proper way to fire form.
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Propliner, Tokay is right in what he wrote but if you want to shoot factory loads it's not going to work.

It may actually shoot very well as is If you headspace off the shoulder, instead of the belt. Lots of people do this.

You could fireform at much lower pressures safely with even stretch.

From what your stated opinion is of the US smith, I would polish that chamber up to a mirror shine and fireform some cases and see how it shoots.
 
You could also fire form factory loads if you have a bullet puller. Pull the projectiles out of the case mouth until you get a decent amount of jam into the lands. If you pull the bullets all the way, you may as well measure the charge weight and subtract a grain so the added resistance of jamming doesn't equate to too much added pressure.
 
Tokay444 said:
You could also fire form factory loads if you have a bullet puller. Pull the projectiles out of the case mouth until you get a decent amount of jam into the lands. If you pull the bullets all the way, you may as well measure the charge weight and subtract a grain so the added resistance of jamming doesn't equate to too much added pressure.
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This is a great idea. I have a collet puller and will give it a go. I hope they'll still fit the magazine.
 
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