Necking 460 Brass down to 338-378

[Dean2]

I have a batch of what is now surplus 460 brass and my plan was to neck it down to 338. Of course you can't do that in a single step without crushing the necks. My original plan was to run them through a 375 neck die first, problem is I don't have a 378 Bee die and the cases are too large in diameter to go into any 375 die I do have. It isn't worth buying forming dies or a set of 378 dies just to neck down 60 cases so I was hoping someone on here had some bright ideas on how to get the first reduction done so I can then run them through the 338 seater then the 338 sizing die. I do have a email in to Bullberry to see if they make one of their inexpensive rigs that will do this. Thanks for any help.


I do have an ad in the buy and sell for some 338-378 brass in case I can't figure this out.

[marky_mark]

I may have one

[fps plus]

I have a cousin that is a psychiatrist and maybe able to help😁 . Thinking. of this makes my spine hurt. I just can’t shoot that kinda rock
Crusher anymore Gonna have some horse power . Good luck on your project

[Dean2]

Originally Posted by marky_mark

I may have one

That would be handy. Let me know once you have time to check. No rush, just trying to get stuff lined up for June.


FPS - the good news is the 338 only has half the recoil of a 460, so relatively speaking a real powder puff. Some like to ride the Horsies on the Carousel in the park, some like riding the Broncs at the rodeo.

[Dean2]

Thought I would provide a bit of an update. Interestingly enough have found lots of once fired 338-378 brass for sale as well as 378. Problem is new brass is $6 a pop and the guys with the used want $4-5 each for it. With 100 cases to size down it is definitely cheaper to buy a forming die or 378 sizer die than to pay for more brass in 338-378.

[marky_mark]

Was nice meeting you dean
I hope those dies help you out
👍

[Dean2]

So, a bit of an update. Marky Mark gave me a hell of a deal on a nearly new set of Redding 378 dies, he is such a good guy I actually had to force him to take money for them. Thanks Marky Mark, they worked great. Here is the result of the resizing operation.

From right to left, 378 brass that was necked up to 460 originally, then for the current purposes necked back down in the 378 seating die with the plug removed, then the FL 378 dies with the decapping gear removed, then partially sized the 338-378 seating die with the seating stem removed just for illustration purposes, you don't really need to 2 step this part, then fully sized in the seating die, and finally the FL 338-378 FL die with the decapping rod and expander button in place. Imperial sizing lube applied liberally goes a long ways to making this easier.

A Guy could probably get away just using the two sizing dies but this is smoother and easier. Brass thickness went from .013 to .015-6. Final outside neck diameter before seating a bullet is .365, so .001 under max. without having to trim the necks. This may seem like a lot of work but when once fired 338-378 brass is $4 each it is worth the effort. New brass is nearly $6 a pop.

[Big Lou]

God! Why have I never thought of using the seating die with the plug removed as a partial before FL sizing when making brass?! Thanks for posting this Dean. You’ve made my life a whole lot easier.

[Dean2]

Something I thought about as I was examining the brass being formed, guys have asked is Redding really a lot better die than RCBS because they are almost 3 times the price. Take a look at the Full Length sized 378 case, 3rd from the right, that was done in an Redding die. Now look at the case FL sized in the RCBS 338-378 die, last one on the left, Notice the Redding done case has a perfectly formed double radius shoulder and a smooth neck to shoulder transition. Now look at the RCBS done case, shoulder is not a perfectly formed double radius, more of a traditional sloped shoulder style with a sharp break over where it meets the body, and the neck to shoulder transition is not perfectly smooth like the Redding one, it actually has a bit of a step in it. The RCBS set works for the forming process but for ongoing reloading I will be getting a Redding 3 die set, with the NK, FL and Seating dies for the 338-378 and a Redding neck die for the 257 Bee to go with my existing 2 die Redding set for it.

[/QUOTE]