I have, what I believe to be a sizing die. This die has a depriving pin, so I presumed it was a sizing die. However, it allows u sized cases to glide into the die body. I can not find any die boxes in my shop that would suggest that I had purchased a 4 die set.


Does this sound like a defective die, a Franken die, or did RCBS make a specific 45ACP depriving only die?

Thanks in advance for your help.

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Judge control not gun control!

An explanation in terms used in reloading would help. Depriving I assume is a decapping pin. u sized case.. no clue..

oh just figured it out... unsized... Doh..!!

Could be a decapping die only... carbide or tool steel.?

RCBS dies are: size, deprime/flare, seat/ crimp

Sounds like you have the deprime/ flare die.

I must apologize. I created this post while outside with my kids and fighting glare on the screen ... I didn't realize how bad the wording and spelling was!

elpac's explanation sounds like it is dead on. I am so accustomed to reloading rifle ammo (where the sizing die contains the depriming pin) ! fear that I grabbed the wrong die.

Thanks for the help!

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Judge control not gun control!

In a couple of my RCBS dies for pistols the sizing die is the de-capping die. (carbide dies) There is a separate flaring die, and bullet seating die. Three die set. The tapered crimp die is a fourth die.

All of my RCBS dies (30 Carbine, 223 Remington, 25 ACP and 9mm) all have the decapper stem mounted on the sizing die. The 30 Carbine, 25 ACP and 9mm all include a separate die that does nothing but expand the case mouth and the third die takes care of seating/crimping.

simple solution would be to pull the stem out of the die and see if there is an expander step on the decamping pin.

My 1970’s vintage RCBS carbide sizing die does have threads you could screw a stem into, however the three die set as sold had sizing as the first step die, as did the old Hornady dies.

With RCBS pistol caliber die sets whether the de-capping stem is in the size die or expander die depends on when the dies were made or the caliber of the die set. This changed sometime in the 1970s-1980s. Earlier sets the de-capping pin is in the expander stem, later sets the de-capping stem is in the size die.

In some calibers there is not room for the collet and nut that mounts the de-capping pin in the expander stem, .32 ACP, and other short calibers!, and the de-capping stem was always in the size die. The later change simply gave better parts interchangeability between the same diameter cartridges.

As I recall the change was made about the same period that the expander bodies were changed from aluminum to steel!

"My 1970’s vintage RCBS carbide sizing die does have threads you could screw a stem into, however the three die set as sold had sizing as the first step die,....." Well, DUH! Sizing is always the first step die!

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Gunsmithing since 1961

All my 9 & .45 RCBS three die sets have the the sizing/depriming in one die.

As a side note on RCBS expander dies, any made prior to 2010 have the tapered style while 2010 and after have a stepped "M" style expander.

Could it be a Lee Universal decapping die? I have one that is labeled a U die.

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NRA Endowment Member

+1 with ALK8944

Check the top/side for the die markings and that should tell the tale.

As a side note if you have a steel size die and contact RCBS they will send you and adaptor, nut and current decapping pin as a retrofit

No need to apologize. There will always be someone who is quick to point out your mistakes. But for the most part this is a friendly forum

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USAF Retired/VN Vet

Just my two cents here, but if an unsized case slides right in I'd bet on it being either an RCBS or Lee universal depriming die. You mentioned .45 ACP cases. If you have access to a larger pistol (or rifle) diameter case, see if they also enter the die without binding (just till you feel resistance so it doesn't jam). If it does you will have your answer. Good luck!

I just bought a old RCBS set of 357 Magnum dies. The ones in the green cardboard box with the picture of the scope reticle shooting the groundhog. There is a sizing die, a de-prime/expander die and a crimp seating die. I only paid $10 for the set and only needed the crimp die. It was a little unusual of a set but I guess it would work if I needed it to. I'm more accustom to the size/de-prime in the first stage, but like I said it would work either way.

As mentioned......
with RCBS 3 set dies, it depends on what Caliber you are loading.

My 9mm #1 die deprimes.
My 38 special #2 die deprimes.