What diameter are fired cases from your 376 Steyr? I am posting this question for a friend who is still having trouble with his Steyr. His unfired brass measures .501", and his fired factory ammo and handloads measure .506". He has had some partial head separations on the second firing (obvious excess headspace, plus a large chamber ). Hornady sent him a new box of ammo, but even though they are slightly longer to the shoulder they still measure .501" at the base. I suggested that he expand the unfired brass to .416, and then partial length size back to 376 to create a false shoulder to eliminate the headspace problem. He did that tonight, but has not fired them yet.

Any responses will be appreciated.

mbogo375 Do a search on the 375 steyr in this forum. The first batch of factory ammo was faulty and caused head seperations on the first reloading. This problem has supposedly been corrected. I donot think new brass had this problem. If I remember correctly the shoulder was pushed back too far allowing the brass to stretch too much on the first firing, which led to head seperations on the first reloading. I have not heard of any problems with the rifles.

Mbogo,

Eric Ching reported the head separation problem, he was using early ammunition. I used ammunition made a year later, and did no find this problem.

I just measured the bases on my Hornady factory ammunition, and found.500" unfired and .504" fired.

I advise setting up the reloading die for partial resizing...jim dodd

Thanks for the replys. I should have made it clear that we were aware of the headspace situation with factory ammo initially, but my friend was concerned about the difference in diameter of unfired cases and fired cases in his rifle. It forms a noticeably larger case above the web, since the thinner brass in this area allows more case expansion on firing. Obviously this leads to more working of the case on resizing.

He fired some loads today that he had first formed a secondary shoulder on as I had suggested, and it certainly eliminated the headspace problem. The chamber diameter though is still the issue. He has considered returning the rifle, but wanted to find out what the chamber diameter is in other rifles first. I will pass along any responses to him when I speak to him again. He has asked me to express his appreciation to all responders.

I asked John Schaefer to take a read on this thread, and to contribute. Here is his take.

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Jim:

Here is the most recent missive on the problem.

I just got the two new sample fired and twice reloaded cases that Eric
Ching did with the die backed out 1/2 and 1 full turn. They both measure
2.396 at the same .432" diameter datum point as used for the previous
measurements (see below).

Sectioning of the case shows the initial stretch groove but it appears
that the case would survive at least a couple of further reloads IF the die
was left turned out 1/2 turn. From previous data it appears that current
new factory empty cases (which measured 2.389" to the same datum) are much
shorter than they need to be initially as these expanded and reloaded cases
didn't mess up the double lock safe position.

My suggestion, which I think is much better that thickening the case web
and reducing the case capacity is for Hornady to more carefully monitor the
head to shoulder length and to set their case forming machines to make base
to shoulder length about .006-.007 longer and to recut their dies to give
the lengthened case when the die is bottomed against the shell holder.

In my opinion this would totally eliminate the separation problem. It
appears that somewhere along the way something got out of spec and remained
that way as you will notice that the dimensions taken from an early lot of
.376 loaded ammo has cases dimensions much different than current primed
cases. I fired some of that early ammo and the !$@! double lock safe
worked fine with it.

As to stocks of the current "short" brass, the solution would be for users
to fireform them using a mild load and a long seated bullet that would
force the case head against the bolt face and allow the shoulder to move
forward and to use a properly cut die for sizing. (It may be necessary to
remove the ejector and spring to insure that case head is firmly against
the bolt face.)

Maybe as a gesture of good will Hornady might supply a free box of
"seconds" bullets for use in fireforming for those folks with a stock of
"short" cases. Mitch @ Hornady has already mentioned in previous
correspondence about replacing any "short" dies gratis.

Original data.

Once fired factory prototype (formed from 9.3x64)** 2.400, 2.399
New factory brass (unfired) [lot 129G2D25201] 2.389, 2.388
Once fired factory brass 2.393, 2.395
Sized once fired factory brass 2.375, 2.376
Resized and fired factory brass 2.395, 2.395
Loaded round (Lot # 99021) 2.396, 2.396

** Not fired in test weapon.

Dimensions are measured to a .432 diameter datum point on the shoulder and
include the thickness of the gauge. All dimensions in inches.

Cheers,

John S.
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He has quite a bit of information on the Steyr rifles and the .376 Steyr cartridge on his web site:

http://home.sprynet.com/~frfrog/froghome.htm

jim dodd

Jim and John,

Thanks for the info. I will pass it along. Forming a secondary shoulder has solved the headspace problem in my friend's rifle, and backing the sizing die off far enough to not touch the shoulder has reduced case stretch. Sandy has decided to keep the rifle, as it seems to have a faster than average barrel, and groups well.

I'm measuring .501 on new unfired brass and and .505 on once fired brass. I think Hornady should address this problem and post lot numbers of all suspect brass and factory loads.

Elmo