308 or 260 sized to 7-08

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sikwhiskey

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Looking at buying Lapua Brass for new M-70 in 7-08, wondering if I should buy 308 and size down or 260 rem and size up? I can turn the necks if necessary and anneal.
I have tried 308 to 7-08 with rem brass, after Full sizing, the brass chambered with a slight feel and I noticed a slight "donut" on the bottom of the neck where the die appears to have not reached. The Lee die was touching the shell holder + 1/4 turn. Kind of leaning towards the 260 brass to avoid this but have never tried it, will it thin the brass to much or not matter? Thoughts?
 
The donut might be the displaced brass, you are making them smaller so the brass has to go somewhere. 260 brass may be the way to go. I have never tried that so if you could find a couple and try it might be the best way to find out without having to buy a bunch. Just my .02
 
I have done exactly what you are wanting to do.Going from .308 to 7-08.

I figured it is better to go thicker and turn than thinner and have issues with the necks.

I FL sized the Lapua brass but backed the die off just slightly, just enough to size the neck, THEN ran it through my 7-08 collet neck sizer(this step isn't necessary, just the process I used).

After that , I fire formed without projectile using cream of wheat method.

Have only neck sized after that point.

The brass will be short , but that is a non-issue , I think it winds up being .010" less but being quality brass all was well.
 
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Go 308 down and just full length size in a 7-08 die and work up loads, don't worry about the donut, it'll iron out with the first firing. You shouldn't have to worry about neck thickness either unless it's a min cut match chamber. I make everything from 243, 260, 7-08 and 358 with 308 brass. Had to buy 2 boxes of 260 and pull and reload them when I took my boy to Africa as none of the 200 rounds he had actually had a 260 headstamp and SA can be funny about that.
 
Thanks for the refresher. I've been considering better quality brass for a while and haven't found 7-08 in stock. Just saw a decent deal on Lapua 308. I might go for it now.

Willy
 
Thanks, Ordered the 308 lapua brass. The donnut on the rem brass did Iron out after the first firing, with 38 grns of Blc-2, Fed 215m primer and 140 grn bullet. looking forward to using Lapua.
This is my wife's rifle, so I won't use BLC-2 or ball powder for reduced loads, will try mag primers and Varget when the brass arrives, as I have plenty.
 
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