How important for accuracy is the OAL of the brass to the actual chamber length? What is an acceptable range? Assuming some variance, do you need to sort the brass by length like you might sort bullet weights?
Ben
Ben
6BR brass OAL
- Thread starter BenPerfected
- Start date
I'm going on my second season with brass that is roughly .020" shorter than my 6 Dasher chamber. It shoots in the .2s and .3s regularly. It seems to make carbon rings a little easier than usual and I have a theory that a little more heat gets focused on the apex of the transition from neck to freebore. It started spider cracking at that junction very early, but they haven't seemed to grow much since the initial scare.
It was a bummer to have to trim cases that did fireform to a more reasonable length, but at the time I only had 100 cases and needed 66 for a match so all were trimmed to the length of the 66th longest of the batch.
So to paraphrase... Gun shoots OK, but won't break any world records. All Cases trimmed to same length. Makes a fatter carbon ring.
It was a bummer to have to trim cases that did fireform to a more reasonable length, but at the time I only had 100 cases and needed 66 for a match so all were trimmed to the length of the 66th longest of the batch.
So to paraphrase... Gun shoots OK, but won't break any world records. All Cases trimmed to same length. Makes a fatter carbon ring.
You certainly don't want your brass to be longer than the chamber for obvious seating and safety concerns.
As for being shorter and considerably shorter [35/1000ths for example in Neary's explanation] and perhaps getting you too into the BR Hall of Fame watch this while you listen very carefully: https://www.youtube.com/watch?v=ZOPf5Iva-Oo
Note: Although the discussions in Jack's videos revolve around the 6PPC, there are numerous principals and procedures that can be transferred to almost any cartridge. And, as he mentions weighing brass and doing a lot of other minor things do not mean a hoot as soon as you encounter a push or a letup. All that little stuff goes out the window. Spend your time reading conditions and learning to shoot the different ones you'll be subjected to over your shooting session.
As for being shorter and considerably shorter [35/1000ths for example in Neary's explanation] and perhaps getting you too into the BR Hall of Fame watch this while you listen very carefully: https://www.youtube.com/watch?v=ZOPf5Iva-Oo
Note: Although the discussions in Jack's videos revolve around the 6PPC, there are numerous principals and procedures that can be transferred to almost any cartridge. And, as he mentions weighing brass and doing a lot of other minor things do not mean a hoot as soon as you encounter a push or a letup. All that little stuff goes out the window. Spend your time reading conditions and learning to shoot the different ones you'll be subjected to over your shooting session.
My preference is to trim to the longest length with safety margin that all my brass will trim to.
The longer the neck, the better the bullet is supported for rough handling, and in theory the more likely it is to be concentric (assuming my dies are doing their job properly).
The actual neck length is not especially critical for accuracy. What is important is a very clean square cut, and consistent wall thickness. Fuss over the quality of the cut and deburring rather than neck length. Deburring can ruin a good trim, so be really fussy over this.
The longer the neck, the better the bullet is supported for rough handling, and in theory the more likely it is to be concentric (assuming my dies are doing their job properly).
The actual neck length is not especially critical for accuracy. What is important is a very clean square cut, and consistent wall thickness. Fuss over the quality of the cut and deburring rather than neck length. Deburring can ruin a good trim, so be really fussy over this.
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