Expander Die for 9mm?


December 14, 2010, 09:37 PM
Question is do I need to use the expander die on 9mm cases? The lee die set came with the expander die but I thought full length resizing was only necessary on rifle cases.

The question came up when I saw some utube video where people are using the Lee turret press to reload 9mm. Unless Im mistaken; I thought I saw the auto disk powder measure attached to the expander die which would mean they are getting FL sized.

Im using a Breech Lock Challenger single stage press and an RCBS Uniflow powder measure so Im not using the press to charge my cases.



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December 14, 2010, 10:08 PM
You need to size it down at least as far as the bullet will be seated, but most folks size the whole case. You can sometimes get away with not using an expander with jacketed bullets, but must expand and bell the case for lead and plated. I use an expander with all my pistol calibers with all bullets.

The Lee expander is a powder through die. The powder measure being used with it has nothing to do with sizing.

December 14, 2010, 10:17 PM
thx walkalong. I understand the powder measure is unrelated to sizing. Just clarifying the reason for my not using the expander.

Actually I have been reloading plated bullets without resizing and it seems to be ok; although being new to reloading its possible im just not seeing any side effects.

I just resized a couple pieces of brass and noticed what appears to be small, superficial scratches on the sides of the brass. Is this ok?

Jim Watson
December 14, 2010, 10:19 PM
I suggest reading the die instructions and a handloading manual.
In short, the steps for reloading a 9mm on single stage are:
1. Full length resize, decap.
1a. You can recap on the press but I do it offline with a Lee handtool.
2. Neck expand-mouth flare.
3. Powder charge
4. Seat bullet
5. Taper crimp

December 14, 2010, 10:51 PM
You can't skip resizing the case.

You will have little or no bullet tension and your rounds will be prone to bullet set back. (a bad thing)

I would highly recommend getting a good reloading manual and reading it.

December 14, 2010, 11:33 PM
You have to size the whole case for reliable chambering and bullet retention. I use a Lee universal expander die. $15 and it bells case mouths on all calibers.

December 14, 2010, 11:35 PM
It seems some confusion exists....

• The "sizing" takes place on the exterior of the cartridge case.
• Then the "expander" sizes the inside and bells (or "flairs") the case mouth.
• Lee supplies their "expander die" hollow so that powder can be dropped in at the same time.
• The "expansion" may not be needed unless the case mouth is collapsed or oval, but "belling" is almost always needed unless you have boat tail rifle bullets.
• Some plated pistol bullets, such as Berry, have a generous radius on the base which aids seating, but this is no reason to skip belling
• Some minimal amount of belling is usually required on pistol ammo to keep from gouging the bullet.

December 15, 2010, 01:26 AM
^^ +1000. Sounds like you're mixing up some terminology.

As for expanding:
Small defects in the base of a bullet can affect accuracy. I suggest pulling some finished rounds to inspect for damage. I found some of my own plated bullets were being damaged this way, so now I put a generous bell on all my pistol brass.

As for resizing:
All auto brass needs FLR'ing. Bolt action or breech loading rifles and revolvers can be FLR'ized or neck-sized.

December 16, 2010, 12:49 PM
agree with above about resizing. if you are getting scratches on the exterior of the case, check and clean the inside of your sizing die. best to use one of the barrel/cleaning solvents like Hoppe's No. 9 or whatever you have. If you need to check the die for scratches, use a dry q-tip.

December 16, 2010, 12:57 PM
The 9mm is a tapered case, and unless you FL size them, you will not have enough neck tension to hold the bullets in place during feeding.
SO, you have to FL size every one of them.

Then neck expand so you can get the bullets to go in.

If the sizing die is scratching cases, you have a tiny spec of brass galled to the inside of the sizing die.
You will have to polish it out with some 600 grit black emery paper of a dowel rod.

You can avoid galled cases in the future by using just a little spritz of case lube before sizing.


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