• This Forum is for adults 18 years of age or over. By continuing to use this Forum you are confirming that you are 18 or older. No content shall be viewed by any person under 18 in California.

New 6 br brass shot 1st time

zap

Silver $$ Contributor
I shot my “ new to me” 6 br barrel for the first time the other day. This is a Savage target action in a SSS bench rest stock, barrel is a 30” 8 twist.
I started loads down at 28 gr when using 8208 xbr, and N133, and varget. On a few of each of those loads i saw some very light ejecter marks on a few case heads, but not on all cases. I shot the loads of each powder with increasing powder charges watching very closely for pressure signs. I saw the same thing all the way to 30 grains. Only 1 or 2 cases of each 3 shot loads had this.
Primers were cci 450’s and were not all that flat. I have seen much flatter with my .223 with some win factory loads in the past.

My question, is it normal to see pressure signs at lower powder charges with new brass ?
 
Sometimes when cases get a run at the bolt face, which is typical with new cases because they typically have several thousandths "headspace" you can get what you have seen. Another thing that I have heard does this is not drying the chamber after cleaning, as well as a little oil/solvent in the bore on the first shot. If you have any unfired cases, use a gauge to measure their shoulder to head dimension and compare that to your once fired. One more thing, it usually takes several shots for cases to reach their maximum "headspace", so I always try setting the FL die to the measurement of the case with the longest "heaspace", size it, one, try it in the rifle and if it chambers OK do the rest with that setting. If I have the time and die, I will NS and load one case with a stout load until its "headspace" stabilizes at its highest value and set it aside for a reference. I do not see any point in bumping back shoulders of cases that are not tight in that direction.
 
Sometimes when cases get a run at the bolt face, which is typical with new cases because they typically have several thousandths "headspace" you can get what you have seen. Another thing that I have heard does this is not drying the chamber after cleaning, as well as a little oil/solvent in the bore on the first shot.
My 250 Ackley Improved chamber was cut a little deeper than typical, so I do not get a crush at the neck/shoulder junction on bolt close. In experimenting with fire forming 250 AI cases "bulletless" from 250 Savage or 22-250, I find I get best results (sharpest shoulder point with least stretching at the web) by wetting the case body slightly with Rem Oil or Kroil.
-
 
My Allen, thank you for the comment. I head spaced my barrel to about .0025 using a fl sized pc of my new brass. My chamber must be on the small size because the new brass was tight when I first tried it right out of the box. I started to bump the shoulder back in .001 increments until the bolt would easily close. I had to bump shoulder about .003 on all so they would chmber nicely.
After fire forming, they all grew about .002 because when I tried a few, I could feel the bolt dragging some when trying to close it. So, I bumped them down again.

I will be sure the chamber is good and clean, and will scrub the throat to be sure i dont have a carbon ring causing any issue.
Thanks
 
Zap,
One thing that you should be aware of is that your FL die may not be small enough to size the brass from your chamber properly. Friends ran into this same problem when they had 6BRs built. I told them to send fired brass in to Harrell Precision and to order a die that was right for their chambers but they had never heard of Harrell's and went ahead and bought Redding type S FL dies. As a result they had to bump their shoulders back more than they wanted to get the bolt feel that they wanted. If your FL die is right for your chamber you can bump cases very little from the shoulder to head dimension of a tight case, and the bolt will close just fine. For instance, .001 is plenty for my 6PPC. Another common mistake is to think that trimming close to maximum is a virtue. I do not believe that it is. I know that in long range benchrest there are some that disagree, but I recommend that everyone watch the series of videos that Jack Neary has on Youtube. There are six short segments of a presentation. The subject caliber is 6PPC but the information is useful for your caliber as well.
 
[...] In experimenting with fire forming 250 AI cases "bulletless" from 250 Savage or 22-250, I find I get best results (sharpest shoulder point with least stretching at the web) by wetting the case body slightly with Rem Oil or Kroil.
-

I shoot ALL of my new cases wet the first time(s) until they have filled out to the chamber and the shoulder is at a stable length - it stops cases from stretching in the first stages of life. I use G-96 oil.

This is also reccomended by Jack Neary in his tutorials on YouTube.
 

Upgrades & Donations

This Forum's expenses are primarily paid by member contributions. You can upgrade your Forum membership in seconds. Gold and Silver members get unlimited FREE classifieds for one year. Gold members can upload custom avatars.


Click Upgrade Membership Button ABOVE to get Gold or Silver Status.

You can also donate any amount, large or small, with the button below. Include your Forum Name in the PayPal Notes field.


To DONATE by CHECK, or make a recurring donation, CLICK HERE to learn how.

Forum statistics

Threads
166,343
Messages
2,216,613
Members
79,554
Latest member
GerSteve
Back
Top