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Reloading 9mm Question

Uncle FesterUncle Fester Senior MemberPosts: 1,453 Senior Member
New reloader Question

First of all, I hate the seating die that came with my Lee 4 die set.  The cheap top part makes it a huge PITA to make fine adjustments compared to my Hornady 300 BO seating die.

Second, the round I am making should have a COAL of 1.125 according to the reloading manual I am using.  Unfortunately, I was getting lengths as low as 1.113 and as high as 1.133 using the same exact setting.

I looked everywhere and could not find any information on the acceptable tolerance on COAL.  

Assuming short rounds lead to a more compressed charge and more pressure, at what point do I need to pull the bullet and re seat it?

Note - I am not loading the rounds hot.  More to the midpoint of the suggested charge of CFE Pistol.


  • earlyagainearlyagain Posts: 7,550 Senior Member
    edited June 2020 #2

    The Lee seating die has an O-ring on the locknut. Tighten the nut so it compresses the ring to hold it snug against the press. The seater should also have an O-ring on the screw in stem to hold adjustment. The actual piece that seats the bullet is seperate. Make sure its oriented correctly in the die. You'll see the correct way easily when inspected. Pistol cartridges don't require the precision of rifle. Bullet length discrepancy will make for COAL discrepancy. New brass is likely within max case length as shown in the included pic, but its good to double check. Taper crimp to the shown neck dia in the SAAMI drawing. Run the loaded cartridges through the Lee FCD. You can use the chamber of your gun as a cartridge guage if desired. Over charges, loose bullets, and COAL must be closely monitored and adhered to as the small cases can give dramatic increases in pressure if the interior case dimension is reduced by bullets being pressed too far in the case.

  • BamaakIIBamaakII Posts: 379 Member
    edited June 2020 #3
    2/100ths of an inch is nothing to worry about IMO.  You won't get much better unless you get something like a Redding competition seating die.  I adjust length A lot with the same load when trying to make power factor or if a load has chambering issues.
  • Uncle FesterUncle Fester Senior Member Posts: 1,453 Senior Member
    BamaakII said:
    2/100ths of an inch is nothing to worry about IMO.  You won't get much better unless you get something like a Redding competition seating die.  I adjust length A lot with the same load when trying to make power factor or if a load has chambering issues.
    Thanks.  They all passed through my case gauge fine. 
    I was just concerned about there being a minimum number that I should worry about.
  • ilove22silove22s Senior Member Posts: 1,464 Senior Member
    edited June 2020 #5

    you may want to disassemble the seating die and see if there are any burrs/crud  and maybe give it a cleaning since you will have it apart anyway.

    if you take apart your seating die, you may notice that the seating stem is of a particular design where the bullet tip meets/fits.   If you want, you may want to contact LEE about this and see what they say.  If you are not happy with their reply, ask about having a stem made for your particular bullet type.  iirc, RCBS offers different seating stems in their sets.

    also, you may want to take a step back when you look at numbers.  I understand some people read things as a bible/law if they dont have a background in numbers.  

    but just understand there is usually a tolerance.  Im not sure what book(s) you use but just understand that you maybe within the tolerance.  your book may or may not address any tolerance.

    as mentioned by Bamaakll, if you look at the largest LOA you measured, its about 0.012 inch off nominal.  If you have any micrometers/calipers, adjust for 0.012 inch and see the difference/gap.  You may get an idea on what you are concerned about.  Numbers are great, but if you dont have a grasp on what that number represents, is all hand waving.  seeing/feeling it, may shed light on that.

    a comment.

      > i do batch reloads. And i use reloading trays.  So what i get after its all and done are loaded cartridges with the bullet facing up.  So part of my process is to put the tray on my table and look across the bullet tops to see how tall/short they are with relation to one another.   I also do the same when i drop the powder into the cases.  I can shed a light into the case at an angle and see the powder level in each case.
    The ears never lie.

    - Don Burt
  • SpkSpk Senior Member Posts: 4,410 Senior Member

    Also, like it was said above, check the tightness (the die should be relatively snug). Check for packing Gunk inside the die. Sometimes they get overzealous and you need to clean them before you use them. If it's still a problem, contact Lee, they might say "send it back."  I did that once when my FCD was having issues, they sent me a new one that worked great.

    For modest to moderate loads, don't lose any sleep over your ammo. Most modern 9's are pretty darn forgiving.

    Never argue with stupid people, they will drag you down to their level and then beat you with experience -- Mark Twain
    How easy it is to make people believe a lie, and [how] hard it is to undo that work again! -- Mark Twain

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