Is it possible to make 358W cases out of 243W?

[Brother_Love]

I know that is a big change. Will the brass reform that much w/o splitting. How would you go about this?
Thanks, BL

[rockrat]

I would anneal the necks on a few cases first before you try it. Might try a fireforming load with a few and if you have the dies,on a few try going to 260 then 308 then try 358w. I have done cases from .284 to .429, but lose about 1/4 of them.

Your necks might be a bit thin.


I have made plenty from 308 brass, till I found some 358w brass. Kind of like 218 bee brass, its out there, but few and far between.

[Brother_Love]

Thanks. I may try trading the 243 for 358 (or 308) first.

[Smoke4320]

Brother Love
how many 308 would you need ?

[376Steyr]

I'd be concerned that the necks would be too thin, and a standard .358 sizing die wouldn't size the neck enough to hold the bullet tightly. It would be wise to check this by making a couple of dummy rounds before expanding the necks on your entire supply of .243 brass.

[Hardcast416taylor]

About 30 years back I helped a fella that had a bolt actioned 358 make cases he could use. We made cases out of .308 brass annealing the neck. He used that brass for many years till he sold the gun.Robert

[GRUMPA]

I make those all the time from 308LC brass. I wouldn't even consider making those from 243 to be honest. Thin necks are a problem as well as annealing the finished product. Just read my signature and you'll notice those are but 1 of many I convert. If you try it get the case gauge for it, many dies on there own wont hold the gauge dimension and require some modification.

Also......I run the parent case through a small base die (almost a must-do) which can and will lengthen the case just a tad.

[Brother_Love]

Thanks for all the assistance!

[Prodigal Son]

I make 358 Win out of 308 Win all the time! One step process to easy!

[Artful]

Anneal 'em and make 'em from 308 and you'll be happy happy happy.

[smokinfeathers]

Ive made plenty of 358 n 356(it will run on 308 cases as well) out of 308 cases simple as lubing them up n running through fl sizing die n then loading them up.