Trimming Lapua 6BR brass to fit in a PPC boltface

adamsgt

adamsgt

Jerry Adams
I have 5 boxes of Lapua 6BR brass that I bought some years ago with Shelly Davidson. He liked the 30BR and we split an order of 1000 pieces. I'm finally getting more serious about making a 30BR barrel to shoot score. The three rifles that I have, A Grizzly II and two Bat all have PPC bolt faces. I discussed this with someone at the Shilen swap meet yesterday and he suggested that rather than opening up the bolt face to just trim the 6BR brass. The 6BR brass measures .468 at the rim in diameter and the 220 Russiian measures .439. That implies that I'd have to take .0145 off the 6BR brass. Are there any particular techniques that work best for accomplishing this? I have a 7X10 and a 12X36 lathe although I only have collets for the 12X36. If I do the trim on a lathe do I need to grind a bit for a specific shape or would a parting tool suffice? Or is there a simpler method that I'm just not seeing?
 
Jerry,
This advice is worth exactly what you paid for it, but if I were going to do this, I would try chucking up a Wilson caseholder and pressing the cases in by hand, then make the cut with one pass, leaving all adjustments the same. There are plenty of folks who have done this, so hopefully they will chime in, and maybe tell me why my idea won't work.

Cheers,
Keith
 
adamsgt said:
I have 5 boxes of Lapua 6BR brass that I bought some years ago with Shelly Davidson. He liked the 30BR and we split an order of 1000 pieces. I'm finally getting more serious about making a 30BR barrel to shoot score. The three rifles that I have, A Grizzly II and two Bat all have PPC bolt faces. I discussed this with someone at the Shilen swap meet yesterday and he suggested that rather than opening up the bolt face to just trim the 6BR brass. The 6BR brass measures .468 at the rim in diameter and the 220 Russiian measures .439. That implies that I'd have to take .0145 off the 6BR brass. Are there any particular techniques that work best for accomplishing this? I have a 7X10 and a 12X36 lathe although I only have collets for the 12X36. If I do the trim on a lathe do I need to grind a bit for a specific shape or would a parting tool suffice? Or is there a simpler method that I'm just not seeing?
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If you are going to rebate 30BR to PPC bases, a specific ground tool will do a MUCH better job and make the job MUCH easier when you are doing your 200th case
 
Something like this:
Rebate_head.jpg

You've got the lathe, and using a Wilson holder works well. It's not hard to grind the tool.
 
Wayne Shaw said:
Something like this:
View attachment 12459

You've got the lathe, and using a Wilson holder works well. It's not hard to grind the tool.
Click to expand...

By the date on the picture, I see this situation has been handled some time ago. However, as the chuck is usually on the left, wouldn't the tool bit be ground the opposite of what your picture shows? Or am I missing something again?
 
adamsgt said:
By the date on the picture, I see this situation has been handled some time ago. However, as the chuck is usually on the left, wouldn't the tool bit be ground the opposite of what your picture shows? Or am I missing something again?
Click to expand...

Just rotate the cutting tool 180 degrees and/or reverse the spindle rotation if necessary............don
 
Don said:
Just rotate the cutting tool 180 degrees and/or reverse the spindle rotation if necessary............don
Click to expand...

I don't intend to sound like I'm nit-picking I just want to be sure I have this straight in my head. As the cutting edges of the tool need relief, If I rotate the tool 180 degrees I'd have to reverse the rotation; just like threading from the shoulder out. Correct? The brass on the left in the picture appears to be the after as it shows shiny surfaces. This implies that you advance the tool until the nub just touches the bottom of the groove. Correct? Lastly, the 6BR rim is 5 thou thinner than the .220 Russian. Any issues for the extractor or ejector?

Grinding tool bits isn't hard, grinding them right is. I haven't ground enough tool bits to consider myself proficient in the process. So, I'll no doubt waste a few getting to the desired shape. :eek:

TIA
 
Obviously it is possible to cut all the surfaces at once but it seems to me that doing it in one cut would put a lot of stress on the case making it want to slip out of the wilson case holder. This is why I do the rim cuts towards the chuck, to force the case into the case holder. When doing the plunge cut I still have to be careful that the case doesn't jump out of the holder.

I have a long steel rod that I leave in the head stock to use to knock the case out of the holder when done. I center it with the spider on the lh end.

Even doing it my way it only takes a minute or so to do each case. I do 20 or 30 and then take a break to let my previously abused neck recover.
 
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More pics from the past. First is my form tool.

34fhcgg.jpg


swv7dz.jpg


My tool was cut with wire EDM after putting both the 6BR brass and the 220 Russian brass on the optical comparator. It is not a hand cut guess thing. The last picture from left to right.
Remington 6br brass without flash hole, 6br lapua brass, 6br Norma brass with rebated rim, 6br Remington brass rebated to 222 size.
 
You have a Grizzley action. Just have Kelblys open the bolt face to .308 It will still work for the PPC and you will save yourself all that work rebating brass.
 
KEITH MYERS said:
You have a Grizzley action. Just have Kelblys open the bolt face to .308 It will still work for the PPC and you will save yourself all that work rebating brass.
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Just got off the phone with Kelblys. They want $68.00 to open the boltface and ship it back. Writing a check seems a lot simpler than trimming 500 pieces of brass. Think I'll get the bolt in the mail today. :)
 
I thought the same thing and ended up just opening the bolt face on two different actions works great w/ either cartridge. Though I will have to say that w/ the Panda I decided I wanted an ejector and had to have a Sako installed to extract the 30 BR cases the standard extractor would not work with the ejector.
 
My action is a drop port which uses a Remington extractor so my options were: 1-buy a BR action; 2- buy a BR bolt; 3- rebate the cases. I originally planned to chamber another bbl in 6Beggs for this rifle so the PPC bolt face worked out good for this [ never realized ] idea :)
 
Ray unless I am mistaken or misunderstanding, you said drop port. The only drop ports I know of are made by Stiller. As memory serves me Stiller can/will open up the bolt for you.
I believe he just posted something similar on another thread.
Even if not there are others who can do it for you.
 
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