Lapua 6BR Primer Pockets

[DJ111]

I am shooting a 6BRX and have killed the primer pockets on my brass. After I fire formed my brass I shot the brass 6 times and have encountered very loose primer pockets and popped a few primers. I measured the primer pockets tonight and new brass is .173.5-.174'' and after a few firings they are .174-175.5''. The ones that blew measured .180-.192''. CCI 450 primers have a diameter of .175.

I am sure I hurt them during load development when I tried up to 33.6 grains of Varget. My current match load was 32.6 grains of R-15 but after I popped the primers I backed it down to 32.2 grains of R-15 with the new brass.

Question is how large of diameter is acceptable before the brass should be discarded?

I would love to know what others primer pockets measure on the brass that they still use with multiple firings?

Thanks,
Dallas

 

[alf]

As long as the primer stays in the pocket your gtg, but if you're trashing your brass in 6 firings, you are running on the warm side.

 

[Travelor]

Obviously your loads were too hot.

But, you might try some Russian primers as they are supposed to be a bit larger to extend the life of your cases.

 

[forsyth793]

If you can find some Wolf Small Rifle Magnum Primers, they will resurrect life in some of the cases. Let us know what you find...

 

[DJ111]

I realize that they were definitely on the hot side, but I was just looking to know if there was a safe measurement one could go by instead of trail and error.

The wolf small magnum primers I have seem to measure the same as the cci 450.

IT shoots great with the hotter loads but I do not want to break the bank on brass! IT took 9.75-10 moa from a 100 yard zero to get to 600 yards using Berger 105 VLD's at around 3080-3100 fps.
New load is 32.2 grains R-15 shooting around 3040-3050 fps.

I loaded some with the .175.5'' diameter to try this afternoon, so we will see what happens.

Thanks,
Dallas

 

[jdfletch]

Lots may vary, but of the several lots of CCI 450's and Wolf SRM's I've tried, the Wolf primers are always 'tighter'. Be wary of primers that easily insert as gas can escape from the edges and mess up your bolt face. The primer may not 'blow', but the damage will be done. 'When in doubt, toss it out.',My Jesse Jackson / Al Sharpton impression of the day!)

Doug

 

[Rustystud]

For you guys who are loosing brass due to loose primer pockets. Wally and Bobby Hart make a swager to restore primer pockets. The tool is about $30.00 and they make them for both large and small primer pocket restoration.

Nat Lambeth

 

[spclark]

'The tool is about $30.00 and they make them for both large and small primer pocket restoration.'

Interesting. These are the barrel-maker Harts? Is their tool only for .475' case heads?

,I'm looking for a way to swage heads on cases made from .25 Remington for 6HAGAR.)

 

[zullo74]

I am shooting a 6BRX and have killed the primer pockets on my brass. After I fire formed my brass I shot the brass 6 times and have encountered very loose primer pockets and popped a few primers. I measured the primer pockets tonight and new brass is .173.5-.174'' and after a few firings they are .174-175.5''. The ones that blew measured .180-.192''. CCI 450 primers have a diameter of .175.

I am sure I hurt them during load development when I tried up to 33.6 grains of Varget. My current match load was 32.6 grains of R-15 but after I popped the primers I backed it down to 32.2 grains of R-15 with the new brass.

Question is how large of diameter is acceptable before the brass should be discarded?

I would love to know what others primer pockets measure on the brass that they still use with multiple firings?

Thanks,
Dallas

This SAAMI chart may help with your measurements....

http://www.northfloridashooting.com/images/Primer_SAAMI.JPG

 

[Bob3700]

EDITOR: This refers to a load for a Dasher or 6BRX. 33.6 of Reloder 15 is dangerous and excessive for a std 6BR.

I have been shooting the Wolf small rifle magnum primers and at about 6 firings per case still have very tight primer pockets.'

105 Bergers at 3020fps shoot small groups, give single digit ES and SD number and shoot very flat.

I am amazed that you are only loosing 40-50 fps when dropping a full grain of powder in the case. IMHO, you are way past the top end on your pressures.

I can shoot 33.6 of RL15 with a 105 Berger but that is getting close to pushing the limit.

Varget loads would be less as it has a slightly faster burning rate.

Find the sweet spot aroung 3000 fps and let your brass live a little longer. If you want higher velicities, get a bigger case.

Bob

 

[spclark]

I get a good 2900 fps using Berger 105VLD from a 26' Kreiger-tubed spacegun upper - it shoots knots @ 600 if I hold hard.

I use 30.5 grains of RL15 in a 6HAGAR case,almost exactly the same case capacity as a 6BR) but with the LR primer in these cases the brass suffers. Tried 31.5 early on but those cases were toast after one firing.

 

[DJ111]

Thanks for the responses! I might order the Hart swagger tool and see if I can save some of my brass or just buy new brass. After .1755 they are no good and will leak or pop. I have since retested loads and backed all the way down to 31.0 -31.8 grains of R-15. 31.4 shot well right at 2996-3009 fps. I am going to do more testing with this load as it should still be alright when it is warmer out as it was only 70 degrees outside. My 32.2 load was still to hot and my pockets were loose on the second firing. I have around 800+ rounds down the barrel and maybe I am having a carbon problem since I never seemed to have any problems in the beginning. Plan is next week to clean the barrel with some JB and retest the 31.4 grain load with the 105 vld's.

 

[Flybuster]

It might be partially due to carbon build up like you said. I experienced some pressure problems too around 800 rounds in my Dasher because I let carbon build up in the throat. I wasn't brushing enough and only using wipe-out as a solvent. It still shot great. I bronze brush it thoroughly with Boreshine then soak with wipeout after every match now. That solved part of the problem.

The other part was while shooting summer F-Class matches in 100 degree temps I had to keep my ammo in a cooler, otherwise strange things happened with RE-15. I had to be very careful on how long to leave a round chambered. I have reduced my loads down to 32 grains with the 105s and 108s, vertical seems to grow if your not shooting high pressure.

 

[dreever]

Personally when working up a load I measure new brass at the web. Then if on the first firing the brass measures more than +.001 I consider the load too hot and back it down. I never want to see brass anymore than .0015 ever regardless of the number of firings. My brass usually lasts 25+ loadings before I encounter the first split neck so then I know it's time to trash can it. I've never encountered a primer pocket problem either. I admit there is always more velocity available with hotter loads, but there is always a price to be paid.

Danny

 

[DJ111]

I picked up some JB and some sweets 7.62 last weekend and spent about an hour cleaning the barrel. I only used a small amount of JB but went at it for quite a bit with the sweets and a nylon brush, also ran a bronze brush through a few times. It seemed to be very dirty and had a lot of carbon and copper fouling. Previously I had been cleaning every 50 rounds with Butch's Bore Shine and also brushing.

Loaded up 5 fowlers and ten rounds each of the 31.4 and 31.8 grains of r-15, wolf small mag primers and Berger 105 vlds .015'' into the lands.

The barrel must have had a lot of carbon build up as I lost about 65 fps from my testing last week of the same loads and weather was the same.

I will be retesting the 31.8 grain load again as it was a 5 shot bug hole with a average velocity of 2979 with a ES of 6.

I also purchased new brass with no plans to fix the old.

Dallas

 

[AckleymanII]

07/30/09
Reply with quote #8

--------------------------------------------------------------------------------
For you guys who are loosing brass due to loose primer pockets. Wally and Bobby Hart make a swager to restore primer pockets. The tool is about $30.00 and they make them for both large and small primer pocket restoration.

Nat Lambeth

+1

The tool will get the job done!

 

[niceone]

let me get thir right 33.5 of rL15 IN A 6BR???????????

 

[Joel]

It's a 6BRX not a straight 6BR