Forming 338 edge from 375 brass.

[wboregon]

I'm pretty confident this can be done, I've seen more then a few people doing it. I just happen to have a batch of 375 rum that was given to me with some other reloading stuffs and just ordered up a barrel and dies for the EDGE.

I'm hoping to size down .375 rum with a whidden bushing die. I ordered a .365 bushing to start with, but I'm really perplexed how you determine what bushing you need while forming brass, or with any caliber for that matter? I know that you measure the neck of a seated round and then shoot for .001-.002 smaller, but it seems like you have to have something to size the brass with first, then determine your bushing and then buy it. which seems kinda like a chicken or the egg situation. any one able to explain best practices there?

Also any one have any general tips or tricks for 338 edge?

 

[Deleted member 46119]

I have a 338 Edge.
I've done a lot of necking up and down.

I'm on my 5th firing of my R-P Edge brass formed from 300 RUM. I have to do something soon. So...

I bought some Atlas DG brass instead. Mine just came and it looks really good. Basically $2 each. If you would like to go down that route, PM me.

Now on to your project. Forgive me if you know some of this stuff. I'm just trying to be complete.

1) As you size down the neck will get thicker. Neck turning is required.
2) Neck turning before sizing all the way down will make that task easier and less likely to have the dreaded doughnut.
3) Annealing is a must.
4) Neck down in about .020 steps annealing every other step.

The necks should start at .016 thick +-.002, so..
.375+.016+.016 = .407 The actual specification is .405

For your first pass, a .390 bushing.
Then anneal.
Second pass .370 bushing.
Your ID now should be about .339 with a neck thickness of .018 +.000-.002.
Neck turn to a thickness of .015 +-.001. Your OD should now be .373
Anneal
Final sizing with a .362 bushing and a .336 expander ball. This should result in a .334 +-.001 neck ID.

These dimensions will all work. Someone else may suggest different dimensions for the bushings but they won't be far off. Take their advice as you will. I'm not perfect just experienced and prefer to do as few passes as possible. I would suggest you add the salt of: do they have a 338 Edge, have they done that sort of necking down.

I recommend a couple spare bushings. Personally I buy +-.001 of each. That winds up being lots of $$.

All those bushings will add up to quite a bit of money. Getting quality brass for less than $3 would probably save money in the long run.

 

[Deleted member 46119]

I just compared the Atlas DG group and my R-P brass to the dimensions above. All within tolerance.

 

[wboregon]

Yup totally understand ever one is going to have a little bit different result when sizing + different brands of brass.

Now the chambers on a 338 edge should be some where around .371-.372 at the neck. the 362 bushing seems small specially if your not sizing up from .300 rum. what bushing are you going to be rocking with those atlas brass, are you planning on neck turning them or?

 

[wboregon]

I have a 338 Edge.
I've done a lot of necking up and down.

I'm on my 5th firing of my R-P Edge brass formed from 300 RUM. I have to do something soon. So...

I bought some Atlas DG brass instead. Mine just came and it looks really good. Basically $2 each. If you would like to go down that route, PM me.

Now on to your project. Forgive me if you know some of this stuff. I'm just trying to be complete.

1) As you size down the neck will get thicker. Neck turning is required.
2) Neck turning before sizing all the way down will make that task easier and less likely to have the dreaded doughnut.
3) Annealing is a must.
4) Neck down in about .020 steps annealing every other step.

The necks should start at .016 thick +-.002, so..
.375+.016+.016 = .407 The actual specification is .405

For your first pass, a .390 bushing.
Then anneal.
Second pass .370 bushing.
Your ID now should be about .339 with a neck thickness of .018 +.000-.002.
Neck turn to a thickness of .015 +-.001. Your OD should now be .373
Anneal
Final sizing with a .362 bushing and a .336 expander ball. This should result in a .334 +-.001 neck ID.

These dimensions will all work. Someone else may suggest different dimensions for the bushings but they won't be far off. Take their advice as you will. I'm not perfect just experienced and prefer to do as few passes as possible. I would suggest you add the salt of: do they have a 338 Edge, have they done that sort of necking down.

I recommend a couple spare bushings. Personally I buy +-.001 of each. That winds up being lots of $$.

All those bushings will add up to quite a bit of money. Getting quality brass for less than $3 would probably save money in the long run.

Also, Do you think neck turning will be 100% required in this situation. I've done 38-55 to 32 special before, as I had terrible problems with concentricity and uneven necks when forming from 30-30. and I didn't have any problems with neck tension or neck thickness.

Major reason I wanted to neck down from 375 rum was to end up with a thicker neck, vs thinner neck from forming up.

I guess I should probably order up a K&M turning tool just incase.

 

[Deleted member 46119]

Yup totally understand ever one is going to have a little bit different result when sizing + different brands of brass.

Now the chambers on a 338 edge should be some where around .371-.372 at the neck. the 362 bushing seems small specially if your not sizing up from .300 rum. what bushing are you going to be rocking with those atlas brass, are you planning on neck turning them or?

My math might not be perfect. .371 chamber means a .369 or less loaded cartridge neck. .369 - .004 f0r .002 tension means .365 bushing minimum.

I have not measured or loaded the Atlas DG brass yet.. probably smaller.