6BRX False Shoulder Formation

G

gilream

Mike
Gentlemen,

I've researched this site on this subject but mostly the debate has been whether to simply jam a bullet into the rifling and fire OR to form a false shoulder, jam a bullet then fire it. Based on experience forming 22PPC cases from 220 Russian brass, I am firmly in the camp of the false shoulder group but need some help as to the tools needed to do it.

I have new Lapua 6BR Norma blue box brass for my new toy. It is chambered in 6BRX with a "no turn" neck that I'm told is .272". I have weight sorted the brass and have expanded the necks using a .257 mandrel from Sinclair.

The sizing die that came with the rifle is a Redding Custom Type S Full Sizing die marked 6MM BRX 30degree. I have .267 and .268 bushings for it but knowing that bushing dies do not size completely to the neck shoulder junction I am worried that this die will not reach far enough down the case neck for the crush fit that I desire.

Will the bushing die that I have size enough of the neck to give me a crush fit on the false shoulder?

Or do you think that I should buy or borrow a standard 6BR FL die to form the false shoulder with? Since I'll only have to size about 1/2 of the expanded neck, using a standard FL die I would be able to slowly move the die deeper into the press while checking the cases in the rifle until I get to the point where I feel resistance closing the bolt...right? Stopping at that point I would then prime, charge the case with a moderate load of Varget, seat a heavy bullet firmly into the rifling and fire it...right?

Thoughts would be most welcome. I hope this make sense.

Mike
 
I owned and shot a BRX for 600 yrd long range benchrest for about 5 yrs. All I ever did was trim brass back .005 under max length of reamer print and bump shoulder back on6 BR brass so it would chamber in the rifle( firing pin assy removed from bolt) and size neck down to .267 ( .269 neck ) and lightly oiled cases with fingers and used a load of 8208 XBR and fire formed. Tried the false shoulder route and it was a waste of extra time. If you decide to go the route I explained you will be able to ladder test loads after one firing they will be 100 percent after two firings.
 
Thanks guys...I bought a standard 6BR FL die and used it to set the false shoulder (after expanding all of the necks with a .257 mandrel). I'm using the Lapua blue box brass, 30 gr. Varget, Berger 105 VLDs seated +.010, Fed 205 primers. Accuracy is amazing at 100 yds. Velocity from my 30 inch barrel is 2835-2844.

I read some "not so stellar" reports about hydraulic forming so decided to go the more traditional route.
 
Why make simple things more complicated?

I have done hundreds of BRX cases simply loading long and firing. I don't understand the desire to find a "solution" to what is not a problem. By the way, BR full length die will work fine. You DO NOT need a BRX die!
 
JEFFPPC said:
I have done hundreds of BRX cases simply loading long and firing. I don't understand the desire to find a "solution" to what is not a problem. By the way, BR full length die will work fine. You DO NOT need a BRX die!
Click to expand...

I'm a bit surprised. What supports the bottom of the case?
 
I remember an article years ago about how much a firing pin would push a case on a hard jam bullet. That's a big bang in a small chamber so I think the case will fill up that space anyway. Maybe just which way the brass flows. A lot of people do it both ways probably doesn't make a difference.
 
gilream said:
I'm a bit surprised. What supports the bottom of the case?
Click to expand...
What supports the bottom of the case, is the bolt face, on the other end is the bullet pushing against the lands, works like a charm.
 
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Tesla said:
What supports the bottom of the case, is the bolt face, on the other end is the bullet pushing against the lands, works like a charm.
Click to expand...

Sorry Tesla, I didn't make myself clear. I was referring to using a standard 6BR die to FL size a 6BRX case. Since the BRX case body is .100 longer than the standard case I was asking "what supports the bottom of the case" while sizing?
 
what I do is back off the sizing die .100 and size the bottom part of the case with a .308 body die
 
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