Re-Chambering tricks

B

bob3700

Member
All,

I am looking to rechamber an older SS 6mm BR barrel to 6 mm BRX. The cartridge is about .100" longer in the body than the original case and the neck is larger in diameter on the BRX reamer.

Is there anything special that I need to know when reaming the new chamber?

I figured that I would center the bbl off the old chamber and then just cut the new chamber deeper. Two bbls will be used on the same action. This bbl will be used as a fireforming bbl only.

The chamber does need to be cut to match the headspace of the main bbl so that the cases will interchange. Any tricks you use here?

Thanks for the help.

Bob
 
Why bother, or is your plan to fireform thousands?

bob3700 said:
All,

Two bbls will be used on the same action. This bbl will be used as a fireforming bbl only.

The chamber does need to be cut to match the headspace of the main bbl so that the cases will interchange. Any tricks you use here?

Thanks for the help.

Bob
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Peter
 
Peter,

Will probably be forming about 500 pieces. Both my brother and I are LR Prone shooters and are chambering bbls for the BRX.

No need to wear out a good match bbl needlessly :)

Bob
 
i used a barrel nut system similar to the savages on my secondary brx barrel
was able to get the fire formed cases within .0005 in length of the ones shot in my bat bartlien match gun
used a junk remington action & shilen barrel for the fireformer
 
I was going to do just that for my F Class 6mm Dasher but decided to get the fireforming proceedure down pat with my main barrel first. Jamming hard doesn't come close to working and necking up to make a false shoulder induced too much runout. I ended up making a hydraulic forming die ram and used my full length sizing die. Of course a shell holder without the primer hole had to be made as well. Oil instead of water and no air bubbles inside the case, no primer to fill the hole was needed. A good whack blew the shoulder forward easily and headspace was perfect but they were very rounded. Too hard a whack and I could see a mark on the case from the vent hole of the sizing die. Now I have no case stretch.
 
Bob,
I've fireformed around 1200 Dasher cases using the false shoulder method in four different rifles. The only real difference between the Dasher & BRX is the shoulder angle, so there shouldn't be any reason why the false shoulder method won't work just as well for your cartridge. I've had no problems with runout in the formed cases, and if there was a problem with runout in the FF ammo, it wasn't enough to cause any problems on target.

And since you're a prone HP shooter, there's no reason that I can see not to fireform while shooting 600yd. matches. That's how I formed the majority of my Dasher cases, and I gotta tell you, the accuracy was plenty good enough to clean the MR-1 while fireforming. In fact, I shot my first 600yd. clean (200-12x) with FF ammo. I use a stout charge of Varget, R 7-1/2 primer, and moly'd S107MKs, which gives 2880-2900fps out of 28"-30" bbls. One reason for FF'ing with heavy bullet match loads - it's a lot easier to get fully-formed cases on the first try with 105-107gr. bullets than dinking around with corn meal or lighter bullets. Another reason - with today's high prices of components, I'm too darned cheap to go blast away at a backstop just to form cases, even with a junk barrel.
 
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