Neck up or down for 7mm-08? Which dies?

[mattri]

Looking to form 7mm-08 out of Lapua 260 or 308 cases.

On the one hand necking down is a simple process, and I could even look at using the small primer Palma cases. At the same time I don't want to run into donut issues and do not want to turn necks.

Would using 260 cases help avoid donuts and/or thick necks? Is there any down side to using 260s?

Either way which dies would you suggest and why?

Thanks, Matt.

 

[brian427cobra]

308 will be too short, necking up 260 will create donuts without neck turning. I know that's not what you wanted to hear buts it's the truth.

 

[mattri]

Thanks for the heads up.

If using 260 brass which die would be best to expand and how best to turn necks?

 

[Elkbane]

Mattri,
I've been exactly where you are. Tried sizing down 308 Lapua cases and tried sizing up Lapua 243 cases (for both a 7mm-08 and a 260 Rem, before Lapua made 260). As another poster indicated, you will get shorter necks using 308 cases. Mine measured 2.013-2.015" before sizing down and 2.018" after sizing and trimming to length. Spec on 7mm-08 is 2.035" with a 2.025 trim-to length recommended. That's not much of a difference and it does give you nice thick necks, which may be to your advantage if you are trying to use bushing type dies in a factory chamber. In any case, you'll have great brass, and pretty uniform necks, although a little short.

Necking up the 243 Win cases delivered donuts, even though I was neck turning. Once you have them, they are a booger to ever get out - even by neck turning. I abandoned that project and pitched the brass.

If it were me, I'd just buy Norma brass in 7mm-08. That's what I eventually did, and IMO it's as good as or better than Lapua. I'm shooting it in a 7mm-08, a 260 Rem, 300 WSM, and 300WSM brass fireformed to 7mm WSM with no issues. It's excellent brass. I do clean up the necks by neck turning, but I'm just anal about neck uniformity - if I wasn't already set up to turn the necks, Id' shoot them "as is" and call it a day.

So, of your options posted, I'd opt for using 308 Lapua brass. But if you aren't set on Lapua, going straight to 7mm-08 Norma brass is what I'd do.
ELkbane

 

[brian427cobra]

Necking up is super easy, run the brass thru a expander mandrel, Sinclair, K&M, 21st Century all make them, then size them as you normally would, I resize Win 7-08 brass into 260Rem, yes Win brass sucks compared to Lapua, but after the full prep treatment they shoot good, I have many 1/2 groups at 200 yards, I use Win brass in my 260 because Rem brass sucks, Lapua is too exspensive, I lose a lot of brass at the matches I shoot in, Win brass does the job just fine.

 

[5spd]

I have run down .308 win brass for my 7mm-08 and have had not a single issue to date.

 

[mattri]

Thanks for all the great replies. I'll take a look at he Norma brass for sure, and if I still decide on Lapua I'll post my results. Thanks again, Matt.

 

[Fordnutter]

I used 308 Lapua brass necked down - in a standard SAMI chamber it let me then neck turn the brass for consistency & still run minimal clearance. 308 brass necked down gives a much thicker neck than 260 or 7mm08 brass - That's why I choice that route.

 

[1holeaddict]

If it were me i would go Norma , Win, or Hornady. Buy it shoot it if it shoots great if not buy a different brand and retry at this point it is still cheaper than buying a neck turning setup and possibly running some lapua brass. JMO

 

[jimbires]

I use norma in my 7-08 . it's nice brass . Jim