can 30-06 brass be reformed to 8x57 simply by running it thru the 8x57 fl die?

The expander ball would open the neck, the sizing die wound push back the shoulder, and you case trimmer would burn the midnight oil.

RCBS makes a forming die for it. The 30/06 is 63mm long so it would have to be trimmed 6 mms to cut its length down to 57 mms.

The neck would also have to be opened up from .308 to .323.

It is do'able but why not just buy 8 x 57 brass, unless you have a lot of 30/06 brass you are not going to use and a lot of time on your hands.

Cheers and good shooting
seafire

I've got a bunch of military lake city brass.these would just be for cast loads.8x57 brass isn't available locally,so its a mail order deal.

8x57 is easy to get. Why bother? There is another factor. You drop one and somebody forces it into his 30-06 and gets hurt. I think it is a bad idea.

Burke, I sometimes convert '06 brass to 8 x 57mm, especially when the latter is scarce. You can use the 8 x 57 die to FL resize the '06 brass, but a forming die is the better and easier way to go. Make sure you anneal the necks afterward and check internal diameter after the first firing. Btw, the reformed brass, even with CB loads, doesn't last quite as long as the genuine article.

Ive got a lot of 8X57 brass from 06. It is easy to do but the thing to watch for is the thickness of the neck. Especially considering the variances youll find in 8X57 chamberings. If your chamber has a tight neck then you will want to thin out the necks to make them safe. I havent had to do that with mine.

I have made a lot of 8 x 57 from 06 brass. I start by running the 06 brass into an RCBS case trimming die, with the die set so the case shoulder to base is slightly too long for 8 x 57. With the case in the forming die take a hacksaw and int on sweep cut off the brass sticking out of the trim die. The trim die is hardened and the hacksaw blade will not hurt it. Then, if you want, you can trim just a little with a conventional lathe type trimmer to clean up the somewhat jagged case mouth.
Then set up a full length 8 x 57 sizing die (with the expander removed for the moment) and adjust the die toward the shell holder a smidgeon at a time followed by chambering the case carefully in the rifle. It may take several adjustments until your get it just right, but the headspace will be just right for your rifle. Replace the expander in the die, then size, trim, and chamfer.
It may sound like a lot of work, but I've taken lots of GI 06's and made very accurate 8 x 57's from them at low cost. At least its low cost if you already have the tools to do it.