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Cartridge OAL tolerance...

Discussion in 'Handloading and Reloading' started by rmurfster, Jan 3, 2007.

  1. rmurfster

    rmurfster Well-Known Member

    I just setup my new Lyman Turret Press that I got for Christmas :) -- I have Dillon 40 S&W Carbide dies. According to the Lee Reloading Data for 40S&W using 155 lead bullets, the minimum length is 1.125" and the OAL is 1.135", so I adjusted my seating die for 1.130".

    However, every few cartridges would produce either over the OAL (sometimes even 1.140" or even under the min length (sometimes about 1.120), which is quite odd.

    Being fairly new to reloading, what sort of variations do you experience with your OAL with finished rounds and should I be concerned?

  2. The Bushmaster

    The Bushmaster Well-Known Member

    I don't load .40 S&W, but I do load 9mmX19 and .45 ACP and I never see anything more then +/- .002 to .003 difference in OAL in either one. Make sure you are using the same pressure when actuating the press. Any change in the amount of pressure applied to the press from one cartrige to another will definately make a difference in cartridge OAL...
    Last edited: Jan 3, 2007
  3. rmurfster

    rmurfster Well-Known Member

    Thanks, however, I'm using the same pressure as far as I can tell. I pull the handle all the way down and the ram inserts the cartridge all the way into the die every time.

  4. FieroCDSP

    FieroCDSP Well-Known Member

    Slow and steady.

    Slow and steady is important. I get near exact lengths when I make sure to use a consistant speed on my Lee's lever. If I rush at any point, I get variable lengths. You might want to make sure that your die is adjusted to remove any play from the shell holder. That would certainly cause a variance like that.
  5. rmurfster

    rmurfster Well-Known Member

    I don't understand. What "play"? I adjusted the die up/down to get the bullet seated to the proper OAL of the shell. What else can I do to make sure there is no "play" from the shell holder?


    HSMITH Well-Known Member

    Lead bullets range from truly excellent to really really bad. Depending on the quality of the lead bullets and the consistency of the bullet shape .020" of OAL variance isn't hard to believe at all.

    Weigh a sample of the bullets, and also compare the nose shapes. To be exact you will need a comparator to see if the nose shape is the same. With Dilllon dies I would expect that using a comparator you will see less than .005" variation but still see .020" of OAL variation.

    Unless you are loading near or at the top of the data shoot some and see how they perform. Odds are they will perform well within the combined ability of you and your handgun.
  7. JMB

    JMB Member

    Make sure you are using the correct seating stem for the bullet shape you are using.
    Just a side note, I'd be more worried about the ones that were shorter than the MINIMUM OAL. It's better to be longer than anticipated and you'll probably find that if you are running these loads thru a semi-auto that longer will feed better. Yes Lee does say 1.135 is the max OAL, acutually SAAMI says that but you have to remember that 1.135 max OAL is guaranteed to chamber in every gun or so that is their intention. But you will find guns that will chamber a longer OAL with no problems.
    If you haven't already make sure these rounds chamber in your guns before you go loading up 100's.
  8. Steve C

    Steve C Well-Known Member

    The "shell holder" may not have been what Fiero meant to say.

    The body of the die is adjusted up or down so that it gives the desired crimp to the case, the seating stem is adjusted to set the depth the bullet will be seated and thus the final OAL of the cartridge. Once the die has been set to the depth where you get the crimp you want you should turn down the lock ring to the press and lock it in place so that the die will be set at the same depth each time its screwed back into the press. The lock ring on the seating stem needs to be tight to keep the seating stem locked in place for the particular bullet you are loading and will most likely need to be adjusted in or out when you change bullet type, weight or shape. Dies need to be kept tightly locked in the press as they may sometimes work loose giving you some "play" thus changing your OAL.

    An accumulation of bullet lube on the seating stem is another thing that will change your OAL.
  9. rmurfster

    rmurfster Well-Known Member

    Thank you

    All excellent posts!
    Thanks alot.
  10. jmorris

    jmorris Well-Known Member

    If your using a progressive press, you need to have a fired case at the sizing station, to ensure everything is lifted up consistantly. The remaining variation will be in the ogive of the bullet. The bullet seating stem pushes from the point where the stem contacts the matching diameter on the bullet, and pushes it from there down a given distance. If you would like to see if your variation is in the machine or projectiles load a few (WITHOUT POWDER OR PRIMERS) with the bullet inverted (like a wad cutter) this will take the ogive out of the equation. If the difference is the same it’s your machine/process, if it’s less it’s the projectiles.
  11. db_tanker

    db_tanker Well-Known Member

    Don't quite know if this was hit on...but I think you might need to take a look at the expander die...it might be set too "low" and causing the cases to be belled too much...

    Also, one other thing...I use the bullet seating die to simply seat the bullet and close up the belled case a bit, then run the round into a dedicated Lee crimp die...I prefer the Lee die due to it isn't case-length sensitive...I use this setup with 38 Special with excellent results. The Lee crimp die also makes sure the round will properly fit the cylinder.

    Might want to look into that.

    Hope this helps,

  12. The Bushmaster

    The Bushmaster Well-Known Member

    I absolutely agree with db_tanker. The Lee FCD is probably one of the best products that Lee puts out. I have heard a lot of "cheap shots" at Lee products (I own mostly Lee), but I have never heard any bad reports about the Lee FCD. It is a must on every loading bench.:)
  13. rmurfster

    rmurfster Well-Known Member

    Thanks, I'll back off the expander a little and see if that makes a difference.
  14. FieroCDSP

    FieroCDSP Well-Known Member

    shell holder

    My appologies if I wasn't clear. :eek: My #19 shell holder for my Lee press has a slight bit of play in it when you move the lever all the way down. You only notice it when you bottom it out against a die, but it probably doesn't affect it when the shell is in it, because the force necessary to take up that gap is applied when the shell hits the die. I mentioned it because if you adjust a die by sight instead of feel, you adjust too loose due to the play. That would cause an inconsistant OAL. More than likely it's his bullets or the seater stem.

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