Piercing Primers with my 6BRX

[Raptor]

Guys I have started to pierce primers with my 6BRX. I started load development with it and found a load that shoots fairly well. Its 33.4grs of varget with a 107MK into the lands .010 with CCI400 for primers.

When I shot it before with this load it was fine but when I shot it last night after cleaning the rifle it pierced a couple of primers and I can now see a slight ejector mark on the cases. According to "My" cronograph its shooting right at 2980 out of my 28" Kreiger.

I have read where you should have the firing pin bushed when shooting these cases. Is this something that needs to be done on my rifle?? I noticed from the begining that almost all the loads have a "Tit" on the primer.

I tried RL15 for the first time last night. 33.3grs shot the first 4 into .3s with me pulling the last round. The 33gr load shot into .450 Once again according to my cronograph the 33.3gr load was also in the 2970 range with the 33 at around 2950 (If memory serves me correctly). Both these loads also had primer spurs but did not pierce a primer.

This is not a bench gun, its a tactical rifle with close to a 3lb trigger and a 3.5x14 Leupold on it and I am shooting off a sand bag. Thanks Guys!!!

 

[Waskawood]

Do you pierce primers right away or after you have shot it for a while? Carbon rings do funny things. If you clean the heck out of it and it doesn't pierce a primer for a while I suspect carbon buildup. I shoot 33.3 grains of RL15 in my Savage PTA with no problems. If that doesn't work you are probably correct in looking at firing pin issues.

 

[DennisH]

Shooting 33.5 out of a Savage PTA with no issue's whatsoever!

I previously had a problem, the sear was worn, replace it, all ok.

What action are you using?

 

[Raptor]

Remington 700, with just over 250rds.

 

[goldy1]

with my BRX i had the same problem. Try using a magnum primer the 400's were way to soft. after i switched the peircing went away

 

[6BRinNZ]

OP - If you had just primer piercing without the ejector marks then bushing the firing pin hole could be a solution or changing primer type. IMO you have two indicators of pressure - an important one being the ejector marks. Primer cratering as an indicator is easily manipulated - bushing the firing pin or changing the primer type to a harder cup will make that indicator go away but doesn't actually change the potential over pressure. Obviously ejector marks are less easily manipulated.

You can get premature pressure indicators by having lube from sizing on the cases and/or over sizing the case. The carbon ring thing can produce a true over pressure situation however its not load related.

The only other thing that springs to mind that's not load related is the case being too long and gets crimped slightly when chambered.

 

[fdshuster]

Raptor: I recently re-barreled a Rem. 700 receiver that I bought, used, Krieger 24" 1-8, chamber cut with my 6 BRX reamer. Started blanking primers ( 3 out of a box of 20) with the identical load that I used when that same barrel was on a Savage mdl. 12. 33 grs. of Varget, 107 SMK, seated to touch, CCI BR4 primers (.025" cup thickness vs. .019" for the CCI 400). Chronographed velocity average of 2910 fps, so we're on the same page there.

Was advised by others to have the firing pin bushed (Gre-Tan), had it done & all is normal now.

 

[6BRinNZ]

Just out of curiosity - did you guys have just primer piercing or did you have other pressure indicators as well? With today's quality components I don't give primer piercing too much consideration on its own (especially when I know that the load is in a typical range as the OP clearly is) but when it appears with another indicator I take notice.

 

[shooter63]

had same problem with 700 action brx fireforming cases broke sears in 2 jewell triggers before sending to gre tan to have bolt bushed problem solved also switched to 450 primers regards shooter63

 

[SDDasher]

+++ on Gre-Tan for your firing pin/bolt. I had exactly the same problem with my Rem 700, so I backed the load down to 28 grains of Varget and solved the problem for fire-forming the brass. I suppose just sending the bolt to Greg solved the problem but did not want to over work the brass,i.e. loosening up primer pockets, etc.

 

[Raptor]

Thanks Guys!! Appreciate all the replys!! I think I will send the bolt in to get it bushed to be on the safe side. What does he charge to do that??? Thanks again!!

 

[fdshuster]

Raptor: $75 + $7 return priority mail shipping. A real quick turn-around time. A total of 7 days from Pa. to Co. and back to Pa.

I sent it usps priority, insured for $300. Lose the bolt in shipping & your rifle will be out of service 'til you can replace the bolt.

www.gretanrifles.com

 

[243winxb]

CCI400 soft & thin. Change primers.

 

[infantrytrophy]

Agree with 243winxb. Your problem is the CCI400 primers.

Try CCI 450's or BR4's, Fed 205, Rem 7 1/2 or Wolf SR Magnum - the cup on these is thicker and will better stand up to higher pressures. The CCI 400's are OK to use only in lower-pressure loads. I don't shoot the 6BRX, but based on what little I know your loads are at or near max., especially with bullets seated into the lands. The ejector mark you mentioned is another indication of pressure approaching max load.

Check this link, there is a table of primer cup thickness for various primers:
http://www.jamescalhoon.com/primers_and_pressure.php

Randy

 

[jkohler]

Raptor
You said you just clean your rifle did you just oil up the barrel after that? I have see primer piercing before from to much oil in the barrel it will case pressure problems for a few round.

 

[Raptor]

Latest update...... I just got back from the range where I shot three different groups. One with 33.2 of Varget and two with 33 and 33.2 of RL15. All the loads had Wolf small rifle mag primers and none of them showed any pressure signs.

There was just a slight spur on the primer, no ejector marks and easy bolt opening. I will try some 450s the next trip out to see how they do.

Thanks for all the replys Guys!!! I really do appreciat the help!!!