sizing after reloading


January 12, 2007, 03:54 PM
On another venue, a shooter once suggested that after a round had been reloaded it was a good idea to resize the loaded case.

I thought about it and can't really think of any reason this would be especially dangerous, and supposedly it makes the reloaded ammo more consistent.

Anyone have any thoughts?

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January 12, 2007, 04:06 PM
If you use a Lee Factory Crimp Die, it ensures that the case diameter is back to spec after all the other reloading steps. Re-sizing wouldn't be dangerous, just inefficient.

January 12, 2007, 04:11 PM
After the bullet is in the case, resizing the loaded round in a regular sizing die will swage the bullet way down in diameter so that it will now be undersized for a good fit into the chamber throat and barrel. It is also a good way to get a bullet lodged into the sizing die. Sounds like a bad idea to me...

January 12, 2007, 04:12 PM
It's not a good practice, but really depends on the caliber, and the die used for sizing. The Lee Carbide Factory Crimp Die for pistol calibers does resize the case to a certain degree, but the sizing ring is larger than the case sizing die. If the loaded round was run into the case sizing die after loading, the bullet would be swaged to a smaller diameter, among other things.

For rifle calibers, it's not a good idea at all. For one thing, the neck portion of the die sizes the neck down to a smaller diameter than the bullet by several thousandths. Then the expander button resizes the neck for the proper tension on the bullet. If you were to run a loaded round into the sizing die again, it will size both the bullet and the neck to a smaller diameter, not to mention the force necessary to drive the loaded round into the die (with the decapper removed, of course). This would make the neck of the case thinner and undersized, and the bullet would no longer fit the bore, providing your press is strong enough to perform this function.

There are other reasons this isn't a good practice, but these are the ones that stand out.

Hope this helps.


Vern Humphrey
January 12, 2007, 04:15 PM
This is called "post sizing" and is mostly used in automatic pistol rounds -- like the .45 ACP -- to enhance reliability by ensuring the loaded round is dimensionally indentical to a new round. I have never found that it does anything for me, though, beyond what a good crimp die will do.

January 12, 2007, 05:15 PM
My S&W Model 52 has a tight chamber. If I load Berry's plated .148gr HBWC bullets, the cases end up bulged too much for smooth chambering, so they get a quick run into a sizing die one last time before going into the box.

January 12, 2007, 05:31 PM
If you use your regular sizer you could ruin the tight fit of the bullet in the case and possibly cause other problems as well. Lee's sizer/crimper is bigger than the regular sizing die. I worry about that even with the Lee. I use one loading .40, but not .45. Saw no gain with it.

The Bushmaster
January 12, 2007, 10:48 PM
I read all these posts and I have to wonder. Who, in their right mind, would resize a cartridge after it is loaded and the bullet seated? I look at my 9mmX19 and my .45 ACP, not to mention my .38 specials and .357 magnums and I note that the bullet has expanded the case as it was seated into the case mouth. Thus changing the outside dimensions of the case. To run this completed round through a resizing die (sanz decapping pin) and if you could without undue pressure on the press handle. Wouldn't you be not only (possibly) damaging the bullet, but reducing (maybe) the bullet to a smaller size. I would also think that one might just get a jacketed bullet and case stuck in the die.:banghead: I absolutely see no reasoning for this in the first place. If one is worried about the size of the cartridge after loading and seating the bullet one should be smart enough to buy a Lee FCD which checks and resizes the cartridge automaticly...:scrutiny:

January 13, 2007, 12:51 AM
Several years ago, I reloaded some .44 spl and ended up with some rounds that would not chamber. I had some old Pacific dies and A mixed lot of brass.
I ran them through my sizing die and they worked fine.
Since then I understand some cartridge companies make .44 spl from .44 Rem Mag brass.
The inside case thickness was larger then the old . 44 spl brass.
Anyway the resizing did no harm.

January 13, 2007, 02:44 AM
Actually, I was tasked with getting a fully loaded .308 OUT of a .308 full length die! This gent had pushed the loaded round into his FL die because he "had some that weren't chambering completely"! The rim was ripped off, just like when you forget to lube a case prior the FL sizeing. Now just how do you go about getting that live round out of there safely?

I was working at a gunshop at the time, we also re-built hydraulic equipment. As we had a lathe, I turned an adapter that would screw into the place where the decapper rod went. The other end would screw onto a porta-power hydraulic hand pump. The oil pressure can reach quite high, IIRC 3,000 lbs-square inch! The first thing to give was the bullet was pushed down into the case, then a few more pumps popped the primer out! Then it was a simple stuck case removal.:) :D

The FL die was undamaged, the gent got a talking to, and a bill for my time!

As has been said, don't do it, even though you now know how to get it out after it's stuck!:what: :eek: :uhoh:

Steve C
January 13, 2007, 02:47 AM
If you are having problems with the loaded round that has bulged or the bullet case wall thickness is making the round too tight to chamber properly then you could use your sizing die to bring it back down some but it wouldn't be a prefered or even a good practice to do all the time. If your reloads have chambering problems you need to fix the root cause before loading any more ammo.

The sizing ring on a Lee Factory crimp die for handguns is a maximum size die that brings any part of the case thats over maximum tollerance back to factory spec. If things are going right the FC sizing ring will not touch your reloaded round and will simply crimp like an ordinary crimp die.

February 14, 2007, 12:49 PM
Another take on this one from the Lee web site.

Referring to the Load Master press.

Five stations so you can Factory Crimp and post size

So apparently, at least Lee feels that sizing after the round is finished is OK.

February 14, 2007, 01:09 PM
Lee says it's Ok with the Lee Factory Crimp Die, which makes sure that loaded rounds are in factory spec to chamber. It doesn't always touch the case walls, as you put on whatever crimp you want, but the occaisonal out of spec case, caused by whatever stresses during loading, will be re sized to chamber correctly. I have 0, zip, nada rounds fail to chamber when using a handgun LEE FCD.
Be aware, the Lee FCD for most rifle cases does NOT do any resizing whatsoever, and merely puts on a nice crimp.

February 14, 2007, 03:52 PM
You can not resize loaded ammunition successfully. It compresses the bullet so it is loose in the brass and re-crimping it won't work either becaseu it is too small in diamer. I tried it the other day on five .40 S&W rounds that wouldn't fit into my gage block and all it did was undersized my bullets so that they had to be replaced.

February 14, 2007, 05:07 PM
If it doesn't fit into your gauge, then there is something wrong with the round. Resizing it isn't the best option, you should solve the root cause. I've never had an issue with or without FCDs (I bought them for grins).

February 14, 2007, 08:03 PM

Actually, resizing was the correct option for those shells because when I installed the resizer on my new press I didn't have it touching the shell plate. I discovered the die was 1/16" off the shell plate, once I reset the resizer die so that it just touched and resized those five casing and reloaded them they were just fine. It just wasn't the correct option with the bullets seated, they should have been pulled first.

February 15, 2007, 08:00 PM
The FL die was undamaged, the gent got a talking to, and a bill for my time!I bet a new die would have been cheaper (and safer).

February 15, 2007, 10:03 PM
Not all cases are created equal :) Some brass has a different wall thickness given the same cartridge and different manufacturer. So to me post sizing sounds like a bad idea.

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