Converting 308 brass to 7mm-08


December 24, 2011, 03:38 PM
I just got a new Savage 114 American Classic in 7mm-08. It's my fourth Savage American Classic, and I'll admit it - I'm addicted. They're beautiful rifles with amazing out-of-the-box accuracy.

I'm getting ready to order the dies, and I'm wondering if I can make 7mm-08 brass out of .308 Win. brass by simply full-length resizing it?

I've made 243 brass in this manner, but the shift to .243 and the Savage's tight chamber require neck reaming after the FL resize. I'm wondering if the 7mm-08 will need the same.

Anyone had any experience with this?

Thanks in advance for any advice,
Kentucky Rifleman

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T Bran
December 24, 2011, 03:54 PM
Wish I had a 7mm/08 sizing die i'd try it for ya but I think it'll work. Just goofing around one day I cut a30/06 case off near the shoulder lubed it and ran it thru my 308 die voila one 308 but it did need some serious legnth sizing. Guess if I'd cut a bit shorter it would have been even closer. Probably a good idea to anneal them before asking that much from the brass.
Sorry forgot to add I also have an AMERICAN CLASSIC in 300 WIN MAG must agree great rifle and it is more accurate than I am congrats on your new addition.

December 24, 2011, 04:04 PM
I anneal before and after moving the brass that much; it just really takes some of the stress off the brass.

Trimming the length isn't an issue; I don't mind that at all. If I had known I'd have to neck ream the .243 I squeezed out of the LC brass, I'd have just coughed up the extra money and bought .243 brass, but the 708 is much closer to the 30 cal neck size than the .243. I may still have to neck ream anyway, which brings me back to the notion that I'd rather buy the 7mm-08 brass than neck ream the 1000 pieces I want.

If I don't have to neck ream, I'll just squeeze them out of LC surplus, which i have a great supply of already. :)


T Bran
December 24, 2011, 04:25 PM
I know how hard it is to wait for all the stuff to get started but I think I'd wait and try the LC neck down before ordering new brass. Odds seem in your favor that it wont thicken the necks very much. I do however agree that neck reaming 1000 pieces would be on my no go list. Try a few if it wont work then order factory fresh.

480 Alaskan
December 24, 2011, 09:29 PM
I have neck down 308 to 260 Rem size, and it worked fine.

December 24, 2011, 10:12 PM
I have read a few articles in 80's American Rifleman "Dope Bag" where shooters experienced pressure issues necking down military 308 brass to 7mm-08.

The reduced case necks were too thick, pinched the bullet, and they had pressure problems.

You need to ensure that the case neck can expand and release the bullet.

December 24, 2011, 10:22 PM
Kentucky Rifleman,

I know this is off-topic, but exactly how do you anneal your brass? Is it just one piece at a time with some sort of torch, or?

December 25, 2011, 02:38 AM
If the 7mm-08 is a factory rifle, then the chamber will be at Least SAAMI sized, which his a neck between .3170 to .3190".

If you FL resize a 308 case with a 7mm-08 die, seat a 7mm bullet, I will be real surprised if you find the cartridge neck measuring .317".

My guess is that it will be less than .315" and it will fit in the 7mm-08 chamber just fine.

But 308 brass in a 243 can lead to trouble.

December 25, 2011, 10:42 AM
ArtP, I anneal one at a time using the blowtorch / tempilstick method. It can be a touch tedious doing 1000 pieces at a time, but it isn't bad, and it still beats watching TV. :)

December 25, 2011, 10:44 AM
Clark, Thanks for the input! :) I ordered my dies yesterday, but the Lee 3 die set won't be in stock at Midway for another week or so. I'll post an update when I get the dies and try 10 pieces or so.


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