6br help needed......

[Glenner]

My buddy got a used 6BR on a Remington Action.
I've done some reloading, but I'm no expert.
We loaded some rounds, but I'm confused by a few things.
1. We bumped the shoulder, but the rounds still chamber tight.
2. The Redding Full Length Die seems to size the neck too small, the inner neck diameter is .233'' after sizing.

These pictures show the inner and outer measurements of the neck AFTER the case has been fired. We did not turn the necks.
Are the normal dimensions for a 6BR fired case?
Is this just a real tight chamber?
Was this chamber cut in a way that requires neck turning?

 

[impalacustom]

A .272 is a no turn neck for a 6BR. It looks like you are going to be buying some neck turning tools, or deal with a slightly tight neck. Savage made some prefit barrels with .271 chambers that will read .270 when fired. What bullets are you using? Sometimes this will make a slight difference in tight necks.

Is this a custom chamber? If so your best bet would be to get a hold of the guy who did the work and try to get the reamer measurements. Or get a cast of the chamber with some cerrosafe and that way you know exactly the measurements and what to neck your brass down to.

You want to try to keep your loaded neck about .002 smaller than your fired neck on your cartridge.

 

[Glenner]

It is a custom chamber/barrel.
We're using Sierra Match Kings, 70Gr., it's a 1:12 twist barrel.

Thanks!

 

[fprefect]

6mm BR

Throats for barrels chambered for cartridges such as the Rem 22 or 6mm BR or the 22 and 6mm PPC will usually have slightly tighter throats than found in most hunting rifles. If you have the specs for the throat diameter of your barrel it should be simply to see if the problem is coming from thickening of the brass in the neck after several firings.

I shoot the 22 PPC and it is not unusual (several years ago) to find small differences in case dimensions although I suspect that would not be the case with the 6mm Rem. However, I would recommend that you only neck size the cartridge thus leaving the case in exactly the same dimension as the chamber, and also I suspect that neck sizing will also produce better accuracy in your rifle than full length resizing and produce longer case life as well.

F. Prefect

 

[bigautomatic]

What brass are you using? If I'm not mistaken, the Lapua is slightly thicker than Norma. My chamber is a no turn neck, but I always turn the necks just slightly just to nock off the high spots. Good luck.

 

[Glenner]

Lapua...

 

[Scorch]

You need to turn the necks. In order to find out the proper neck dimension, you could do a chamber cast, or turn .001"-.002" off the necks, then fire and measure the necks. You need the ID of the neck to be at least .243 after firing so it releases the bullet safely.

 

[Clark]

I have chambered a Sav99 and a Rem700 in 6mmBR with my .272" neck reamer.

But you need to measure the inside diameter of your necks with pin gauges.

 

[amamnn]

If it is one of the older versions of the 6mm BR Remington, as it sounds like, you will indeed need to turn the necks to some degree. You can get some very good info on proper neck turning techniques for the 6BR rem, on the sites-benchrest.com and 6mmbr.com. The current issue of Precision Shooting also has an article with useful info on the 6mmBR cartridge.

The currently popular version that is causing so much talk - and spin offs - in the BR world is the 6mmBR NORMA, which is generally shot using a .272" neck CHAMBER, and which both Lapua and Norma both make brass. I have used both and prefer the Norma. Sad to say, I have had a lot of oddly formed primer pockets and strange neck and shoulder expansion with 2 recent lots of Lapua's brass for this cartridge. Talking to some other BR shooters, I found I was not alone. Bruno's shooter's supply has the Norma brass in stock as of day before yesterday at a price not much more than the Lapua. You should take care to be sure that your decapping pin is not oversized for this case. It does use a slightly smaller primer flash hole. Some people swear that this makes a HUGE difference in performance--some have drilled the flash holes out.