Redding Case Expander Too Small

[justindad]

My .357/.38 case expander from Redding (the premium expander, advertised for use with lead bullets) resulted in brass swaging my 0.3577” boolits down to 0.3570”. Redding technical service told me all is good. I told them lead should typically be 0.358” coming out of the brass, or larger. They replied: “If your targets are ok, it’s only a thou.”
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That’s a pretty strange response. My groups with a 9mm were cut in half when I switched from a 0.356” sizer to a 0.357” sizer. Just because it’s not leading and you hit the paper, doesn’t mean it’s right. I’d prefer it if my boolits came out of the brass at 0.358” (assume I get a larger sizing die).
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Seems like the tech support at Redding doesn’t know what he’s talking about. Am I looking at this wrong?

[BK7saum]

Exactly what size is the redding expander?

What is the alloy or hardness of the alloy? Usually I can load 38 special with fairly soft alloy and they dont get sized down by the case. If your alloy is very soft, that could be part of the problem.

That said, I sometimes use an expander the same size as the bullets I am using. They still have sufficient neck tension for my purposes.

[PJEagle]

In my experience, Redding makes a lot of very good equipment. You can't beat their dies if you use jacketed projectiles. The problem is their dies usually don't work well with lead boolits because of the greater diameter.

I use NOE expanders for all of my calibers. Problem solved.

[Randy Bohannon]

All of my Redding dies have Buffalo Arms case expanders also RCBS have replaced expanding dies as well.

[Char-Gar]

If your bullets are swaged down it means your alloy is too soft for the expanded case. A 357 expander will work for most case bullets that are not butter soft. If your bullets are soft, an expander the size of the bullet is needed.

I use Lyman 310 expanders with a thread adapter in my press. They come in .357 or .357, .452 or .454. I match the expander to the bullet hardness and get no swaged down bullets.

[justindad]

I can’t find Lyman 310 dies - AE they discontinued? Buffalo Arms will make a customs expander for $22, and its long for flush seating wadcutters.
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The alloy I’m working with right now is 96-2-2. The guy at Buffalo Arms asked about that when figuring the diameters of the expander plug.