Making .338 WM brass

1899

1899

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What are you guys doing with the lack of new brass out there? I have +200 1x fired 7mm RM brass that I have annealed and am thinking of necking up, but I have only ever used new brass in the past - 22-250 to 250 Savage, 7mm RM to .257 Wby and .308 NM etc.

Interestingly 308 NM is available new and that would be straight forward but quite expensive.
 
Just go with the 7mm RM, I used .338 WM and 7mm RM brass to reform to .358 NM and .308 NM and even if the neck is a little short at first, it goes back to normal quite fast with a stout load. Actually, for the .338 WM, you can use about anything that wear a beilt...
 
What are your thoughts on necking up once fired brass? I annealed them so it should be fine, no?
 
Take 4 case and either COW form or neck up... you will have your answer real fast.

The problem area is the headspace of the rifle vs brass. Fired belted magnum is going to stress the area around the belt. If you have sized well under the new chamber, separation is very likely.

Confirm that the 7rm will headspace tight into the 338WM chamber... if it is loose, I would be shy to use given what could happen in the field if a case splits.

If you want new brass, pm or email.

Jerry
 
About 12 grains of Unique, COW and a soap or wax plug. Blows the shoulder out and makes a fun 5 yard shotgun for shooting grasshoppers. I've done once fired without much problem, and lost a few new ones. Annealing can't hurt if done properly.

The head space isn't going to be one bit worse than every belted magnum factory load ever loaded, or every load put up in new brass without a false shoulder, which when you think about it is just about all of them.
 
I have necked up two boxes of 7mm Rem Mag to 308 Norma, and it is still going strong. Did the first box many years ago for a friend of mine who had no ammo. We had a whack of 7mm mag, so just did it. No case failures, but he has lost a number of brass over the years while hunting, so last year I did up another box for him.

No reason it shouldn't work fine as 338 Winchester, particularly since the shoulder will not get blown ahead like it does in the 308 Norma Mag.

PM sent,
Ted
 
Just read your first post again. Since you have already annealed the brass, fireforming with COW like Dogleg has posted is probably the best method. Trying to neck up annealed brass sometimes collapses the shoulder. I always neck up fired brass first, and then anneal before loading. You will know after trying to neck up a few of your annealed cases.

Making 25 Copperhead from 222 Rem, those few 308 Norma Mags from 7mm Rem, and 9.3X62 from 30-06 taught me a lot of lessons. A tapered neck expander made on a lathe out of an ordinary 7/8X14 bolt sure simplifies things.

Still learning,
Ted
 
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I found a bag - actually a CGNer generously sold it to me - of new W-W .338 brass. But I thought I'd give it a go anyways.

7mm RM brass, 1x fired and annealed. I started with a .308" expander and just opened up the neck. Then I put the .338 expander into the dies and opened up the neck, but did not FL size. After the neck was expanded I FL sized. There seems to be some donuting around the base of the neck, but it is very minor. I made up a couple of dummy rounds and they chamber fine.

Tried with .300 WM too. It was a pain in the ass. First one split. Then I annealed the next one. That one expanded OK but when I went to FL size I got folds in the brass by the junction of the neck and shoulder. So I annealed another one and used dry powder lube. still some folding. So I annealed another one necked up, trimmed, and tried again. Still the same.

At any rate, as pointed out, 7mm RM is the way to go. I re-invented the wheel but had a bit of fun doing it.

BTW, the length of the finished brass was 2.490". When I started it was 2.495"
 
I just load 'em up as 7 mag and fire them in the 338 chamber...........voila, 338 WM and the case mouth comes out square. I had 100 rds of factory 7 mag one time and no rifle for them, but I needed some 338 brass so BANG, oh look 338 brass...........
 
c-fbmi said:
I just load 'em up as 7 mag and fire them in the 338 chamber...........voila, 338 WM and the case mouth comes out square. I had 100 rds of factory 7 mag one time and no rifle for them, but I needed some 338 brass so BANG, oh look 338 brass...........
Click to expand...

I really appreciate your "solutions man" style of problem solving. Fast, simple, effective. My wife doesn't always appreciate it when I do things this way, but I'm on my first one, so MMMV.
 
c-fbmi said:
I just load 'em up as 7 mag and fire them in the 338 chamber...........voila, 338 WM and the case mouth comes out square. I had 100 rds of factory 7 mag one time and no rifle for them, but I needed some 338 brass so BANG, oh look 338 brass...........
Click to expand...

LOL...

I had a blank look on my face when I chronographed H4831SC and 250 Partitions - 2550fps with a full case of H4831SC. 225's were moving out at +2800, which was OK. Thought about you Doug and your general disdain for the .338 WM.
 
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