RCBS 32-40 Cowboy Expanding Die

[jnutz19]

I just bought a RCBS Cowboy 3 Die set for 32-40. The sizing and seat dies work perfectly. The expanding die on the other hand isn’t working to well for me. I’ve tried it many different ways and can’t get it to work right. I go from no flare and no expansion to a very small flare and too much expansion. I can push a RCBS 32-170-FN sized to .322 straight down into the case with little force. I’m using starline 38-55 brass converted to 32-40. Anybody else have problems like this with the RCBS cowboy dies? I know the expanded die is made to expand the case a little more then normal for cast bullet but mines too much. Thanks


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[EDG]

Have you measured the diameter of the expander plug?

I just checked my RCBS Cowboys dies in 32-40. My dies are unused and the expander plug measures .3215. Which is a little big unless used for a single shot. My dies might not be tight enough for a tube magazine rifle.

If you used Starline .38-55 brass did you anneal it? Starline brass tends to be really hard and might spring back more than you would expect when sized.


My new old stock Bonanza 2 die set (like the current Forsters) measures .3200.
My old 1970 dated RCBS 2 die set has seen heavy use to the point the interior is bright from being polished by the brass. That expander also measures .3200.

[jnutz19]

Have you measured the diameter of the expander plug?

No I haven’t


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[EDG]

I added more to my first post above.

[jnutz19]

Mine measures .3205”. I’m not sure if the brass was annealed or not. I did not convert it to 32-40 but I did run it through my sizing die when I got it.


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[EDG]

Posted sizes of 2 more .32-40 expanders.
If the top of your sizer is threaded RCBS could supply you with the decapping rod assy from a 2 die set.
If you need a smaller expander you might call RCBS and see what they can do or you can spin polish your existing expander down with 320 grit wet or dry carborundum paper used wet with a light oil to keep the paper from loading up.

[jnutz19]

Yea I never thought about that. I also just got some Winchester 38-55 brass that’s been converted to 32-40 today. I’ll resize some it it and run it through the expander die and see if it’s the brass or the expanded plug. I’ve also got some actual 32-40 brass coming too.


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[jnutz19]

Well a little update. I resized the Win 32-40 brass (was converted to 32-40 from 38-55 before I got it) and then ran it through the expanded die. I got the Win brass to expand and flare just enough to accept the 32-170-FN (sizer to .322) boolit with being able to push it into the case. So apparently it has to do with the starline 38-55 brass that was converted to 32-40. What shall I do?? I used my Lee universal expander to flare the the case the first time. Guess that’s what I’ll have to do with the starline brass.


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[EDG]

I would anneal the Starline. Then i would use a Lyman M die to expand it. The M die made for the 8X57 Mauser can be polished to the size you need.