Necking down .308 brass to 7mm-08 in one go

[harlow]

Hi guys,

Can someone tell me, to neck down .308 brass do you just put it through a 7mm-08 full length sizing die?

Is that all? Just a single pass and it's done?

Or do you need to do any intermediate steps?

Thanks.

[yoshie]

That should be it, but do a 1/3 stroke, then 2/3, then full stroke to make sure it doesn't jam and use more lube than normal. I make 260 out of 243. Same amount of change but other way. I prefer to go up, as if you go down you end up with more brass in the neck, gets thicker. Check them when you do it, you may end up with too thick necks. You should be right, but if not you will have to neck turn your cases. Unless you have a really tight chamber you won't have any problems

[Aster]

Yes, you should be able to do it in a single pass.

You might lose a few cases if the odd one crumples, but it shouldn't happen often.

Like Yoshie mentioned, the necks will pick up a little thickness which can cause chambering issues in some rifles, but most accept them no problems.

[Chronos]

Yep, one pass....don't forget the lube

I did 300 cases this way when I bought my 7-08 as I had lots of lapua from my .308

I've never had any problems but I did skim all the necks to uniform them after fireforming

Chronos

[SendIt]

Like Yoshie mentioned, the necks will pick up a little thickness which can cause chambering issues in some rifles, but most accept them no problems.

Neck turning will solve that for you harlow.

It would be ideal if you could turn them all, not critical though.

[yoshie]

308 to 7-08 should be no worries, 260 can get a bit thick and about half of people get problems, 308 to 243 most chambers will have problems, and need to be trimmed a lot as well. If you're shooting a sporter/factory rifle it should be ok, custom target rifle with tight chamber, you will most likely have issues. Let us know how you go.

[Lorgar]

Yeah, it'll be right.

I guess you've got a .308 and are swapping to a 7mm-08? I'm thinking about doing the same and will have 300 brass to resize for it too.

I can upload a picture when I'm home later... I've resized .308 down to .243 in the past and could do it in a single pass with no problems, and .308 to 7mm-08 is less of a change than that.

I'll post a picture anyway just FYI so you can see the result.

[Carter]

I've resized .308 down to .243 in the past and could do it in a single pass with no problems

That's a fair step down in one go. I know a bloke who does it the same but does .308 > 7mm > .243

No need for the intermediate 7mm die in your experience though obviously?

[Lorgar]

I can upload a picture when I'm home later... I've resized .308 down to .243 in the past and could do it in a single pass with no problems, and .308 to 7mm-08 is less of a change than that.

Here's that picture, Harlow.

.243 vs .308 necked down to .243

243-necked-down-308.jpg (62.6 KiB) Viewed 6216 times

Case on the right is the necked down .308, done in one pass. Left case is factory .243 brass.

The top of the neck on the right looks like it has rings around it, but that's just lube/grime.

[harlow]

Thanks Yoshie, Chronos, everyone...

Sorry for the late reply, been away for a bit.

Thanks for the picture too Lorgar. Looks good.

[Lorgar]

That's a fair step down in one go. I know a bloke who does it the same but does .308 > 7mm > .243

No need for the intermediate 7mm die in your experience though obviously?

Nope, works fine straight up.

Necking down is easier than necking up though in my experience.

A lot more elbow grease required to go up to up from .243 to .308. Getting consistent neck wall thickness was a bit of an issue too.

TBH though I was only mucking about with .243 > .308 and only did a few for fun.

[Carter]

Cool, cheers.