Necking down a case from 378 weath to 338-378weath?

[enigma]

I was told if I got 378 weatherby case's I could neck them down to 338 but I've tryed it with the 338-378 die I used to take the primer out and resize the case but it seems to look a little funny the case doe's and a little longer How should I do it?

 

[Buffalobob]

I'm skeered to ask why you didn't just buy 338-378 Wby in the first place.

OK.

couple of things to look for

1 watch out for split necks. If it looks quesionalbe throw it away.

2. The radius will be different on the shoulders and you will need a mild load to blow out the shoulders correctly.

3. The double radius shoulder is designed for gas flow purposes, not strength. so when you begin to apply a lot of vertical pressure from the die you can actually push the neck right down into the case.

That's all I know and I have never attempted to do what you are doing.

 

[enigma]

They are new and they were cheap but I don't think now it's worth the griff.

 

[James H]

When you say the cases look a little funny, what is it about them that looks funny?

One concern when necking down brass is that the brass will get thicker in the neck when diameter is reduced. Make sure that a loaded round's neck dia. is no larger than the neck dia. of a fired round. If it is you will either need to ream the necks or turn them so that the neck dia. of a loaded round is equal to or less than the neck dia. of a fired round from the gun you are loading for (ideally .001 to .004 less).
Also when you resize them, some of the brass will be extruded and make them longer so you will need to trim them or they will be too long and could cause an unsafe condition.

RCBS makes case forming dies to do what you are trying to do but they are expensive.
I hope this helps.

 

[Hired Gun]

Just sell or trade them for the right brass. They are worth more than the brass you need.

 

[Sam11]

I use 378 brass to make 338-378 cases. I use a 338-378 neck sizer die and it works fine. I do trim them as part of my normal routine of trimming cases every time I reload them. If you do use your full length sizer die just size the neck and not push back the shoulder. If you are still not happy with the 378 brass I might be interested in purchasing it. Hope this helps. Sam.

 

[enigma]

I'll sell them to you 40 case new.378 weatherby

 

[enigma]

I hit the button to soon $45.00 and you can have them and that includes mailing to.

 

[Sam11]

enigma: Send me an e-mail, I have a few questions. Thanks, Sam. [email protected]