Nice find Cam, where did you get that from?
Lapua .284 brass life
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Cameron Mc
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aaronraad
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Interesting Lapua went away from 'Mutnz Metal' to C2400. Muntz Metal is one of only a few brasses that is can be hardened by heat treatment instead of work/strain hardend.
There isn't much difference between Mutnz Metal, High Brass and DZR (dezincification resistant brass). DZR has traces of arsenic but the XRF result doesn't include this element.
Couldn't see As listed on the XRF at work either but it had a few CuZn+other elements listed.
There isn't much difference between Mutnz Metal, High Brass and DZR (dezincification resistant brass). DZR has traces of arsenic but the XRF result doesn't include this element.
Couldn't see As listed on the XRF at work either but it had a few CuZn+other elements listed.
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bruce moulds
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is this problem caused by an alloy change, or could it be due to heat treatment differences?
we are all wary of getting too much heat into the base of a case while annealing.
keep safe,
bruce.
we are all wary of getting too much heat into the base of a case while annealing.
keep safe,
bruce.
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aaronraad
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Heat treament for Muntz Metal and C2400 are different.
Each deep drawing application is unique as to how one manufacturer work hardens their particular brass. Heat treatment then not only becomes unique to the material but also to the forming process. Changing material is not a simple process and requires internal R&D to perfect the correct heat treatment process.
It's also the historical statistical data that you lose when you change material. Help determine if a fault is just a one off or a trend.
A little off topic, but here is a report addressing ADI's concern over base case annealing from 1980. You don't see many ADI report listed with the DTIC.mil web-site:
http://www.dtic.mil/dtic/tr/fulltext/u2/a094136.pdf
Each deep drawing application is unique as to how one manufacturer work hardens their particular brass. Heat treatment then not only becomes unique to the material but also to the forming process. Changing material is not a simple process and requires internal R&D to perfect the correct heat treatment process.
It's also the historical statistical data that you lose when you change material. Help determine if a fault is just a one off or a trend.
A little off topic, but here is a report addressing ADI's concern over base case annealing from 1980. You don't see many ADI report listed with the DTIC.mil web-site:
http://www.dtic.mil/dtic/tr/fulltext/u2/a094136.pdf
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ecomeat
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RDavies wrote:A previous post said there is a new lot number coming out, how about we wait to see how that lot goes.
When i was at the QRA "Shootenstuff" shop last week, I asked Jenny if they had heard anything about some new Batch Lapua brass, and she said that they had just taken delivery of a sizable new order, but when I got her to check the batches, it's still the second, of the two batches we have been seeing here in Qld in the blue boxes. BUGGER !!
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DenisA
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Hi All,
I finally got an official email back from Lapua:
Because we weren´t able to get sample cases, investigating of this issue was difficult. We did get a lot
number of claimed cases and there we can track down to our own test results from the time of manufacturing
of this case lot.
Hardness of sample cases from this lot was according to our specification, measured from inside and outside
of the cases. To lots which you mentioned were quite similar regarding the hardness results. We also
compared the hardness results to earlier case lots, but there were no major differences.
Also our results from reloading tests which is performed during case manufacturing was showing positive
results - we have had no loose primers or gas leakage aroung the primer.
Question about changed recipe is good, but answer is that we haven´t made such changes to this case
caliber, which could affect to case durability negatively.
We are sorry to inform you that we are not able to find the root cause for loose primer with these claimed
cases. We are sorry for the caused harm of this issue and to compensate the defected cases we would like
to send you 2 new boxes of 6,5-284 cases.
We wish you will have more satisfactory experiences in future with our products.
With best regards,
Nammo Lapua Oy
Ville Alakoskela
Quality Engineer
So.... they're not saying that the cases aren't different, just "not much different" and that they deem the difference to be within their spec's.
Sounds like living in hope that Lapua will acknowledge the issue is a pipe dream.
As I suggested in an earlier post, it may be a different story if everyone thats had the experience got on board and wrote them an email.
Anyway, a couple of free boxes of .284 brass is handy. I wonder how many boxes they'd give away before re-considering
I finally got an official email back from Lapua:
Because we weren´t able to get sample cases, investigating of this issue was difficult. We did get a lot
number of claimed cases and there we can track down to our own test results from the time of manufacturing
of this case lot.
Hardness of sample cases from this lot was according to our specification, measured from inside and outside
of the cases. To lots which you mentioned were quite similar regarding the hardness results. We also
compared the hardness results to earlier case lots, but there were no major differences.
Also our results from reloading tests which is performed during case manufacturing was showing positive
results - we have had no loose primers or gas leakage aroung the primer.
Question about changed recipe is good, but answer is that we haven´t made such changes to this case
caliber, which could affect to case durability negatively.
We are sorry to inform you that we are not able to find the root cause for loose primer with these claimed
cases. We are sorry for the caused harm of this issue and to compensate the defected cases we would like
to send you 2 new boxes of 6,5-284 cases.
We wish you will have more satisfactory experiences in future with our products.
With best regards,
Nammo Lapua Oy
Ville Alakoskela
Quality Engineer
So.... they're not saying that the cases aren't different, just "not much different" and that they deem the difference to be within their spec's.
Sounds like living in hope that Lapua will acknowledge the issue is a pipe dream.
As I suggested in an earlier post, it may be a different story if everyone thats had the experience got on board and wrote them an email.
Anyway, a couple of free boxes of .284 brass is handy. I wonder how many boxes they'd give away before re-considering
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