dirty brass

[blinky]

hey guys,I was trying to work up a load for my 6br.I just got it and did not really know where to start.So i loaded some 70grSMK's with 29.3grs of N-135.It Shot pretty good for a starter load but after the first 3 shots my brass where getting really dirty around the base.Also didn't look like all the powder was burning in the barrel.

 

[jonbearman]

It sounds like a mild round that didnt seal the breech(chamber),also look into the powder very carefully to see if you need a magnum primer. You may have to check neck tension if you are using bushing type dies. According to my hornady manual your load is at the top.However these are manuals written by lawyers. Is this new brass or has it been fired alot? Size a case and measure the inside diameter of the neck.If you only have a thou holding the bullet,you may want to change bushings till you have about .004 tension.You can also seat your bullets into the rifling to increase the pressure spike.

 

[blinky]

was using cci br4 primers. bullets where load to sierra's recommend oal,didn't check neck tension,but the bullets seemed tight when I seated them.

 

[jonbearman]

Are they (the bullets) being seated to book overall? If the barrel has a long throat,then seating them closer to touching the rifling may be possible. I would also ask what temperature it is outside when you are shooting.If it is really cold then try another powder or use cci magnum primers to light it up. I use h 322 and have never had any problems with sealing the breech such as this.How old is the powder? What kind of rifle is it,is it custom chambered or factory? Try to post as much imfo as possible. How full is the case with this powder? Something is fishy about this,do you have any wolf rifle primers as they are fairly hot?

 

[necchi]

You START with a Max load?

 

[blinky]

new lapua blue box brass,rcbs FL dies,just bought powder[don't know how log been on shelf].Shooting a new savage 12 lrpv[factory breech].IT was 51 degrees

 

[jonbearman]

Did you blow any primers? If not,try another powder like h322 and start lower and work up.

 

[dansig]

hey guys,I was trying to work up a load for my 6br.I just got it and did not really know where to start.So i loaded some 70grSMK's with 29.3grs of N-135.It Shot pretty good for a starter load but after the first 3 shots my brass where getting really dirty around the base.Also didn't look like all the powder was burning in the barrel.

I am shooting 70gr SMK and 68gr Berger, I use 33gr N-135 behined the SMK and 33.5gr N-135 behind the Berger.anything under 32gr is to mild, at least for a 13.5" twist barrel like mine.
I'm shooting sub .2" groups with 33.5gr N-135 and Berger 68gr.

 

[SS427]

According to the Vihtavuori 2006 reloading data that can be downloaded off their website, the starting load for N135 in a 6mmBR with Sierra 70 grain HPBT bullets is 29 grains and max load is 33.9 grains. Sounds like you might want to increase your powder charge.

http://www.vihtavuori-lapua.com/downloads.php

In my 6BR rifle I found 32.4 and 33.9 to be the best N135 loads. This is with a 13.5 twist 24 inch barrel. Brass comes out of the chamber very clean. I use Federal 205m and Rem 7 1/2 primers. Never saw a need to use magnum primers, although I did try CCI 450s but didn't see any difference.

Sierra's load data is very conservative for the 6mmBR and N135. Not sure why. I started there, but soon started using the Vihtavuori data. Even at 33.9 I never got any signs of pressure. Ended up using the 32.4 node as it was slightly more accurate.

 

[blinky]

anyway this could have been caused by to much neck tension? didn't really check.