From .243 or .308 to 7mm-08

Hey everyone, I don't post on here much and its been a while since my last post but here it goes.

Before the recent mass shortages i ordered a 7mm-08 bbl from Jim and decided to wait on purchasing brass and such for components for it. Well the time is coming to start gathering everything else up but brass is rather difficult to locate for 7mm-08 at this time. A friend of mine just recently sold of a .308 and a .243 so i was thinking of getting his old brass from him to re-chamber into 7mm-08. out of the two choices which would you recommend, sizing up the .243 or necking down the .308? Thanks in advance for any advice.

necking down from 308

In a factory barrel either way would probably work. In an aftermarket barrel with a tighter chamber the 308 necks may turn out to be a little thick. If your friend is willing to give you a few pieces make a dummy round of each type of brass and measure them. Also make sure they chamber OK without any extra effort before you commit.

But I agree with Keeki, neck down if possible.

Thanks for the reply's. The bbl is going to be a varmint contour criterion pre-fit so I don't know how tight the chamber is going to be. Besides that I'm still waiting on the bbl to show up, hopefully in the beginning of March. I was leaning towards necking down mainly because I didn't like the idea of thinning out the brass in the neck. Again thanks for the input I think I'm going to grab what he's got laying around for now then wait for the bbl to show before going one way or the other. On a side note, I did find some nosler brass and norma brass on midsouth's website and was curious as to which one is better. I may try to get some next paycheck if its still available.

I say that because necking down will cause your necks to be a little long and you can trim to length. Necking up may cause some split necks and may also come up a little short

Thanks keeki that makes good sense.

ET,
The relationship Keeki pointed out would only hold true if the parent case had the same nominal length. .243 has a length of 2.035". New Lapua 308 brass has an average length of 2.015". WHen you neck down the 308 brass, you'll gain a little length, but the last batch I did with Lapua brass ended up 2.018". That's well shorter than the 2.025" of off-the-shelf 7mm-08 brass, but the brass was very uniform, had nice thick necks, and shot fine. Should be fine if you keep a watch on carbon accumulation in the throat. Since then, I've just switched to Norma 7mm-08 brass and it's about the best brass solution I've found for the 7mm-08.

Current load is Berger 140 gr Berger hunting VLD's, 42g of Varget and Fed210M primers - it's a day in - day out one-hole group load in my well-used barrel. Wish I'd found this load 3500 rounds ago......
Elkbane