Home Forums Reloading Big Game Rifles 358STA question

Will the .35 Remington LEE neck sizer collet die work ok to bring .375HH brass neck down to spec?

I'm fairly sure it'll be OK, but just want to ask others.. Bullet for both is .358, so it should just be a matter of adjustment re: length of case...

I think the only thing you would need to worry about is that the 35 Rem die doesn’t contact the body of the case before the neck gets to the collet section.

If you have the 358 STA dies you could use the sizer on your 375 H&H brass and gradually go lower and lower, testing for the neck length that chambers with slight resistance, creating a false shoulder. Then you’d have a good shoulder for headspace with later loads.

I agree that's a concern.
I do have the die set. But we tried one case, very carefully, only part way through the neck and when we withdrew the case the neck was out of concentricity with the case, by a rather wide margin.. However, we did not go further (at the time), hence the question in this forum.

My son contacted LEE re: the .35 Rem neck collet die and was told by a rep in their tech department it should work OK. I'm not sure. He ordered the die (last one at MidwayUSA) and we'll see how it works. It was rather cheap IIRC - maybe $25.

In the meantime, I'm going to try that case again in the .358STA sizer die and adjust to fully allow the case to get all the way in the neck and see what it looks like.

You may need to make a little collar to go between the top of the shell holder and the bottom of the collet sleeve. The height of the collar will make up the difference in the head to neck lengths between the two cartridges.

Instead of the top of the shell holder pressing on the bottom of the collet, now the top of the shell holder will push the bottom of the collar, and the top of the collar will then press upward against the bottom of the collet.

Just thinking out loud, hope I'm making sense.

Would an intermediate die work to start the squeeze down? A 9mm or 38/357 carbide die will get the OD down to c.370-.372". A 222 die should get OD below .370" if needed. Lack of support on the 375 case taper may still be a problem. Will it straighten out after fire-forming?

My 358 Norma brass measures c .380" loaded

Not a bad idea - never thought of that... Well, it might IF the round can even get chambered with a non-concentric neck..


You are, and I'll consider everything at this point..

Thanks to all..

Well, I gave the STA sizer die another shot on a once-fired .375 HH case. but this time screwed down all the way.. Came out well, but wouldn't chamber. WTH? Checked HS, cleaned the chamber (brand new, never used), measured everything on the case - all easily within limits..

Then it hit me. DUH! I had failed to over-cam the die in the press.... Geez. Did that and it chambered like it should. We're going to fire-form a few cases this weekend, then try a load that's a bit under max.

Take a folded beach towel for your shooting shoulder. 😁

I've formed several hundred STA cases by simply necking down 375H&H cases in my RCBS STA dies and fireforming with no problem at all.