Necking down problem(.308 to 7-08)

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sliceman

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I am a new reloader and have been reloading 7-08 recently, using WW brass. Based on the positive comments about Lapua brass, I recently obtained some .308 Lapua, planning to neck it down to 7 mm as I read on this site that this was fairly easy to do.
I was under the impression that you just needed to run them through a Lee collet type die to do so, but only succeeded in crumpling the neck and shoulder of the 1st one. I backed off the cap screw of the same die, beveled the outside of the neck, and got the mouth of the neck of the next case reduced with a bit of pressure, but with more pressure the mid-neck area crumpled.
I also have both Forster and RCBS full length sizing dies (for 7-08) but have not tried these yet. I will wait for your responses before I ruin any more cases.
Any suggestions or help you can offer would be much appreciated.
 
To neck them down, I just use an FL die the first time around to form the brass, then the collet die thereafter (eventually, you may find they need another FL sizing after several firings if they become 'sticky' to chamber).

The necks may be thicker than specified, but unless you have a tight necked match chamber, you probably won't have to turn the necks down in order to chamber the resized brass.
 
Watch out for fat necks after necking down from 308 to 7mm. The neck thickness will probably be around 18 thou and a loaded round MAY be too fat without neck turning... Neck thickness is usually around 12 to 14 thou for a parent case
 
Lube the cases well - including the neck - both inside and out - will minimize case cave-ins - none needed on shoulder...

I've gone down to 243 from 308 with relatively few problems but do get the occasional crushed neck. Never had a problem with neck thickness - every round has chambered without issue.

Good luck!
 
I just did 100 Lapua brass to 7mm-08 from .308.

My neck thickness wound up being .014"

What I did was FL in my RCBS die.Used a generous amount of spray lube, it gets in everywhere you need it.

After that I annealed the neck/shoulder area.

Fireformed the brass without a bullet, just fast powder and cream of wheat to fill the case.Toilet paper to prevent spillage out of case.

Cleaned the brass.

Neck sized with the Lee collet sizer.

Now ready to load.

Only thing is I am just a tad short .012"-.015", but I am sure the brass will be at length after a trip to the range with test loads.

I have tons of Remington brass for 7mm-08 no issues with it, but not near the consistency of the Lapua.
 
Thank you for your responses, I will try the FL die tomorrow.
Would there be any advantage to using a .308 FL die without the decapping pin first?
 
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