Lapua .284 brass life

ecomeat · Post by **ecomeat** » Wed Mar 27, 2013 9:20 pm

Alan,
I think there might be a number of us waiting keenly to hear your results !
Maybe we will all find out the hard way how much it will take for Lapua to admit to a "small problem" :roll:

Tony

Cameron Mc · Post by **Cameron Mc** » Wed Mar 27, 2013 10:11 pm

AlanF wrote:This has got me worried. I'm going to do some testing in the morning, testing identical loads with 180gn VLDs with older P00532501 and newer P00620601. I notice the latter is the same as Rod Davies reported problems with.

Alan

Alan it will be interesting what you find. I also have 600 of the .....601 batch for the USA trip. Fingers crossed.
I have fireformed 100 so far. Will try maybe 2 cases with high end loads and see what happens.

Cheers
Cam

Post by **AlanF** » Wed Mar 27, 2013 10:17 pm

Cam,

I'm waiting to hear back from Denis and Matt to see what their problem Lot No.s were. If I find a serious problem in the morning I think it'll be time for a "class action" of our members. :evil:

Alan

Brad Y · Post by **Brad Y** » Wed Mar 27, 2013 10:58 pm

I hear there is finally a new shipment arrived of lapua brass again- maybe you guys can find some success in the new lot!

Post by **AlanF** » Wed Mar 27, 2013 11:05 pm

Maybe...

aaronraad · Post by **aaronraad** » Wed Mar 27, 2013 11:25 pm

If the Americans were able to talk Lapua into making a 308W Palma case with a small rifle primer, maybe they were able to talk them into thinning out the brass to maximise case capacity? THe US market is becoming more influentual.

The other alternative is a heat treatment issue in that Lapua heated the entire case instead of just the neck as the final step.

290 deg C is the maximum temp for stress-relieving Cu70Zn30 brass before it starts to hardness and tensile strength. (“cartridge brass.” (From Metals Handbook, 9th Ed., Vol. 4, American Society for Metals, Metals Park, Ohio, 1981) see pp 34 in this link for the figure 10-31 http://web.nchu.edu.tw/~jillc/me/Ch10-%20Kinetics%20-%20Heat%20Treatment.pdf

A quick hardness test around the case head should show if they have started to anneal and lose hardness (<Hardness: HRH 115 to 120 ).

I wonder what Bruce Betram would say?

Post by **AlanF** » Thu Mar 28, 2013 12:37 pm

Okay the quick answer from my testing this morning is that Lot P00620621 is no worse than my earlier lot (P00532501), and both are acceptable, but this was a very small sample (3 from each). I'll learn more over time if it wasn't typical.

A brief description of the method. I took the 6 new cases and fire-formed them with a lightish load and some 175XLDs (at least they're useful for something!) Then I loaded 180VLD molys jammed with increasing loads of N165 (BR-2). Both case lots were loaded identically (in pairs) starting at 57.5gns, then 58.5 then increasing in 0.5gn increments to 60.5gns. Each case was used twice in this for 6 shots of each lot. Up to 59.5gns there was no perceptible change in required seating force, and no change in the extractor groove diameter. At both 60.0 and 60.5gn for BOTH lots, I noticed a slight reduction in required seating force and this was confirmed by a 0.0005 (half a thou!) increase in extractor groove diameter. It says something for the uniformity that there were no odd figures.

Incidently its been p***ing down all morning so no chrono. But from previous measurements with the same barrel and components, 57.5gn equates to 2820fps, 59gn to 2890fps, not sure what the stiffer loads got to but it must have been significantly above 2900. This is in line with all my previous experience i.e. push the 180s over 2900 and pockets will suffer!

So for me, its not panic stations to find some Winchester brass or mounting a class action against Lapua. Whew!!

Alan

Brad Y · Post by **Brad Y** » Thu Mar 28, 2013 12:42 pm

Is that a shehane chamber Alan? Did you keep reloading and sacrifice the cases when you werent happy with the primer pockets?

Post by **AlanF** » Thu Mar 28, 2013 12:47 pm

Yes Brad, 7 Shehane. All the cases are fine, even the worst affected are still better than what I would normally discard. I didn't continue mainly because of running out of space for the powder (the 180VLDs go relatively deep in the case).

Alan

DenisA · Post by **DenisA** » Sun Mar 31, 2013 11:23 am

AlanF wrote:Cam,

I'm waiting to hear back from Denis and Matt to see what their problem Lot No.s were. If I find a serious problem in the morning I think it'll be time for a "class action" of our members.

Alan

Hi Alan,

My current batch thats got loose pockets is LOT P00577401.

I'm in the process of prepping LOT P00620201. This lot number has been identified earlier by Rod and later by Tony as a batch that they've had problems with.
I'll be running mild 180g loads in these.

I still haven't heard any more from Lapua. I'll see if I can get an update from them.

Post by **AlanF** » Sun Mar 31, 2013 11:47 am

Denis,

I'm going to go with the Lot P00620621 for the FCWC. With the current shortages, I'm not going to gamble on hoping to find something better - need to start prepping and fire-forming now. With a slow powder and molying it seems I can get 2900 with 180s, and possibly 2950 with shortened brass life.

In my opinion, if we want to be guaranteed of 2900+ without the problem, we should go with one of the magnums - and shortened barrel life.....

Alan

DenisA · Post by **DenisA** » Sun Mar 31, 2013 5:19 pm

AlanF wrote:Denis,

I'm going to go with the Lot P00620621 for the FCWC. With the current shortages, I'm not going to gamble on hoping to find something better - need to start prepping and fire-forming now. With a slow powder and molying it seems I can get 2900 with 180s, and possibly 2950 with shortened brass life.

In my opinion, if we want to be guaranteed of 2900+ without the problem, we should go with one of the magnums - and shortened barrel life.....

Alan

According to my chrony, my batch P00577401 loosened primer pockets at at 2850fps with AR2213sc.
The accuracy of the chronny........... ?? The figures seem inline with other published loads of similar component combinations though.

I'm currently tuning a load at 2730fps which is grouping very well. Load density is still high too. I still have seating depth to tweak. I only want this Cartridge for 500y - 700y. I don't think I'll need the extra if I'm not trying to reach out further.
I shot this undeveloped load at 700y last week and it was great. How competetive against hotter .284's with 180's in the same conditions is yet to be seen.
I'll only be running the P00620621 on that load. It will be interesting to see its affect on P/P's.

Matt P · Post by **Matt P** » Sun Mar 31, 2013 7:37 pm

Alan
My suspect batch is P00577401, but a fellow club member has the P00620601 batch and lost 33 cases after the second firing (primers fell out while tumbling the brass).

Matt P

Post by **AlanF** » Sun Mar 31, 2013 8:18 pm

Matt,

I've used Lot 577401 in the past, and it seemed about the same as 620601 (with my loads). With Lot 532501 that's now 3 blue box lots with reported problems. Are there actually any other blue box Lot Numbers of 6.5-284 brass in Australia? Maybe all blue box brass is affected. Unfortunately, the more widespread the problem is, the less likely we'll get a fix. I've heard mention of other Lapua cases such as 308 and 220 Russian becoming softer in recent years.

But with these horror stories of primers falling out, I'm now wondering if the problem is occuring intermittently within lots. I have 4 boxes of 620601. I've already taken 3 from 1 box and tested. Will take 3 from each of the other 3 boxes and do the same test. If they all come up without serious problems then I'm just going to put a "speed limit" on the 180s of say 2880 and get on with life.

Alan

bruce moulds · Post by **bruce moulds** » Mon Apr 01, 2013 9:09 am

an interestiing link pertaining to this subject.

http://yarchive.net/gun/ammo/cartridge_expansion.html

ultimately the case is the pressure vessel and must be treated as such.
whatever the case is it must be regarded accordingly.
keep safe,
bruce.