6.5 x 284 Brass

[Matt P]

Hi All
Has anyone else having issue with loose primer pockets using 6.5 x 284 Lapua brass in their 284's. I'm running a light load of 2209 (50.9 with 180 Bergers) and after 3-4 firings the pockets are getting quite loose, is this common or do I have a soft batch of cases ??

Matt P

[DenisA]

Hi Matt, I've had 2 firings out of mine. In the first firing there were some load tests with AR2213 that reached 2900fps. They loosened primer pockets a little but that was consistant with all the advice given to me.

After the second firing I've noticed that the remainder are starting to loosen up quite noticeably too. I'm only running 2800fps with these.

I've been a little suprised and have wondered what it will mean longevity wise.

All the above with 180g Hybrids.

[Cameron Mc]

Matt, I think it maybe the new brass. I have cases that are 5 years old and are still quite usable. These have had at least 10 firings.

Cameron

[AlanF]

Matt,

I've tried quite a few powders (2213, 2217, N165, RL22, RL17, and 2209) and noticed that 2209 was the worst for primer pockets, probably because its the fastest (I have used 2208 for fire-forming but very light load). Maybe the faster powders do more of their work in the barrel sooner, which raises pressure. With N165 I can get 2900fps with reasonable case life. This is a Shehane, so a 284 might be 30fps less. My gut feeling is that the new blue box brass is every bit as hard as the older stuff, but I haven't done thorough testing.

I think the head size is the achilles heel of this case. And I've only had problems with 180s. The Berger 168s can be pushed much harder without primer pocket consequences. Even the SMK 175s can be run at mid 2900s in the Shehane.

Alan

[macguru]

Maybe the 7mm SAUM is a bit stronger case wise ?? Alan do you prefer the 284 class for accuracy reasons ?

Andrew

[Cameron Mc]

Matt,

I think the head size is the achilles heel of this case. And I've only had problems with 180s. The Berger 168s can be pushed much harder without primer pocket consequences. Even the SMK 175s can be run at mid 2900s in the Shehane.

Alan

You have a point there Alan. I have only noticed the greater expansion since going to 180 Bergers.

Cameron

[AlanF]

Maybe the 7mm SAUM is a bit stronger case wise ?? Alan do you prefer the 284 class for accuracy reasons ?

Andrew

Andrew,

Not so much accuracy as cost e.g. need for a new action or at least a different bolt for the magnum boltface, and I heard some pretty horrific stories about barrel life when running the 180s over 3000fps. If I was going to do it now for the FCWC where cost can be justified, I might go for something hotter than the RSAUM e.g. 7mm WSM.

Alan

[RAVEN]

What is a loose primer pocket??
One where the primer pocket accepts a primer less firmly than new or when a primer can not be held within the case at all.
There is allot of variation in-between the 2 of these examples.
I have a set of cases that have been reloaded more than 25 times I would and still do use them in competition I have not lost one case because the primer will no longer hold in and yes the primer pockets are looser than they were new!
RB

[AlanF]

What is a loose primer pocket??
One where the primer pocket accepts a primer less firmly than new or when a primer can not be held within the case at all.
There is allot of variation in-between the 2 of these examples.
I have a set of cases that have been reloaded more than 25 times I would and still do use them in competition I have not lost one case because the primer will no longer hold in and yes the primer pockets are looser than they were new!
RB

Richard,

I've never had it happen, but I once saw the consequences when primers were too loose with a 284. Shots started dropping out the bottom, and burn marks appeared round the primers - so I presume that it would be like a cutting torch into the bolt face. It was the last range of a 2 day OPM, and the shooter was in a winning position until the problem struck with about 5 shots to go. He said those last few cases were from a different set, and had loose primers, but I don't know exactly how loose. For that reason I don't let mine go until they're close to falling out. Its hard to describe, but if there is any degree of smooth resistance when hand priming (RCBS), then I don't cull.

Alan

[RAVEN]

Yes I agree Alan gas leakage from the rear will surely damage the bolt face and effect accuracy.
I have had more issues with 6X47 brass than the 284 flavoured stuff from Lap
I always inspect the primer pockets after firing and if I see signs of leakage I would ditch the lot.
RB

degree of smooth resistance when hand priming (RCBS),

Good discription Alan

[DaveMc]

Yes the case head is the "achilles heel" (Alan) of this wonderfully accurate case. Due to the small surface area it suffers from roughly 13% more force on the case head at the same chamber pressure. Theroretically the 284 should run at 2950 easily (case volume wise) but we always pull up with "case head issues"
I started noticing primer pocket damage to one here and there in my boxes last year so looked further. Most damage (in my routine) was being done in the first couple of shots of the day (clean barrel, chamber etc plus cool barrel).

Firstly I started making sure the chamber was completely free of oil with degreaser of some sort (have tried a few but now use an action cleaner spray) this helped but occasionally I still had trouble. The first shot of the day (that has low velocity) seems to run at high pressure? Seems Less of an issue as the barrel ages.