Can I move a case shoulder back on a lathe?

maple_leaf_eh

maple_leaf_eh

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I have a couple thousand 30-06 cases to donate to the conversion process to make a couple hundred 8mm Mauser. When I tried using the resizing die I found it just crushed the shoulders. My Tool Using Male mind wondered if it would be easier to push a forming tool against the rotating case to move the shoulder back the required 5 or 6mm. If it works I also have to make some 7.5x55 MAS.

The tool in my mind's eye is to hold the case in the jaw of a lathe with a decapping pin in the neck as a rest. Then I see a roller or slippery forming tool (high density plastic maybe) pressed against the moving the brass.

Any suggestions?
 
I have reformed about 1000 30-06 to 8 mm using a RCBS 8mm die with no problems except that I had to flare the case mouth first before running through the die. The RCBS 8mm sizer die dies expander ball is not tapered far enough to make the pass through the 30-06 neck. The neck and shoulder will crush if I didn't flare the case mouth first.
 
Try Imperial Sizing Die Wax.
I reformed a lot of cases to 8mm. Removed the decapping stem, ran them into the die, trimmed, and then into the die again with the expanding/decapping stem in place. Chamfer and load.
Little case loss. As gunn pointed out, if there isn't enough taper to the expander, might be necessary to flare them first.
 
You would be ahead to simply trade the 30-06 brass for 8x57 brass or sell the 30-06 and buy new 8x57 brass. It's not like you can't buy 8x57 anymore and the new stuff will have the proper headstamp.

Mark
 
I got one suggestion.

Put an add in the EE looking for 8mm Mauser Brass, and another selling the '06 brass.

If you really need to size them all down, good lube and a press is gonna be way more useful to you than a lathe. Between issues with holding them, and with trying to come up with a sizing die that will work, you'd have your work cut out for you.

Cheers
Trev
 
gunn69 said:
I have reformed about 1000 30-06 to 8 mm using a RCBS 8mm die with no problems except that I had to flare the case mouth first before running through the die. The RCBS 8mm sizer die dies expander ball is not tapered far enough to make the pass through the 30-06 neck. The neck and shoulder will crush if I didn't flare the case mouth first.
Click to expand...

My dies are Lee. I do have a chamfering tool which I can try. Do you trim the neck back before sizing, or let the neck material 'gather' in the die?
 
There's got to be some place for the brass to go, if the case hasn't been trimmed.
A Lee decapping stem might have enough taper to expand the neck in one go.
Trim them, flare if necessary, fl size, chamfer.
Apart from trimming, it is little more work to form 8mm than sizing fired brass.
Worth mentionning again that good lube, like Imperial, can make a difference.
 
They might be collapsing because they run up against a hard stop in the die. Try trimming the 30-06 to about 58mm then flare, lube well and size down in increments (screw the die out 1/4" inch size, turn in 1/2 a turn, and repeat until the die is against the shellholder). If that works, do the same without trimming (or try that first for that matter). If still no luck, try annealing the neck and shoulder of a few of them and see if things improve.
 
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maple_leaf_eh said:
My dies are Lee. I do have a chamfering tool which I can try. Do you trim the neck back before sizing, or let the neck material 'gather' in the die?
Click to expand...

After the neck is flared, not chamfered, I just use the regular RCBS case lube and run the case in the die in one stroke. The die has plenty of room to handle the excess. After forming, trim the excess with a mini tube cutter and finish the final length in the case trimmer.
 
I used a hacksaw and cut approx 1/4 in off the case then full length sized and trimmed them, all using Lee tools & dies. No probs this end. (Then 7.62NATO gave me a bunch of RP 8mm brass) Now I is a happy camper!
 
sunray said:
"...on a lathe..." No. Just fire form 'em. Mind you, 8mm Mauser brass isn't hard to get.
Click to expand...

FIREFORM!!??Please explain how you would fireform 30-06 brass into 8 * 57mm brass. As I understand it, fireforming involves chambering a mild load cartridge into a rifle and firing it downrange, thereby the brass takes the form of the chamber you are firing it in. Please enlighten me as to how you will chamber a .30-06 cartridge in a 8x57mm chamber to accomplish this.
 
maple_leaf_eh said:
My dies are Lee. I do have a chamfering tool which I can try. Do you trim the neck back before sizing, or let the neck material 'gather' in the die?
Click to expand...
My 8x57mm dies are Lee and the decapping pin/expander mandrel is very sharply tapered. I took it apart once to clean it and noticed that.
It should do the trick. However, You have a great deal of resizing to do here and trying to do it all in one step is difficult.
First you should trim them to length (57mm), then re-size in stages. You not only have to expand the neck, but move the shoulder back and change the body taper a great deal. You will need lots of lube for this project.
As has been posted earlier, save yourself the trouble, sell the brass and buy new 8mm stuff. You will be happier in the long run
 
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