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Using an auto pistol barrel find a MAX O.A.L with your bullet

Discussion in 'Handloading and Reloading' started by Walkalong, Feb 20, 2010.

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  1. BBQJOE

    BBQJOE Member

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    I understand almost all of this.
    Is the .015 setback a universal "given" for best bullet performance?
     
  2. 918v

    918v Member

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    No.

    If you are counting on .015" bullet setback your handloads are improperly assembled.
     
  3. bds

    bds Member

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    Here's definition of all three - http://blog.sinclairintl.com/2009/03/26/determining-bullet-seating-depth/
    My Sig/M&P/Glock/Lone Wolf barrels look like the picture below with just the leade but the KKM barrel I have has the additional "throat/freebore" cut in the leade (I will post comparison pictures later when I get some clear shots).

    [​IMG]
    Some pistol barrels have longer leade than others. The picture on the left (white arrow) shows a Lone Wolf 40S&W barrel with typical leade length I have seen in many factory barrels. The picture on the right shows Sig 1911 TacPac barrel with almost no leade. My latest 40S&W Lone Wolf barrel for Glock 23 also has almost no leade like the Sig barrel. The longer leade barrel allows for longer OAL of the finished round typically used but the shorter/no leade barrel forces you to use shorter than typically used OAL.

    [​IMG][​IMG]

    For M&P45/RIA 1911 barrels with longer leade, I can load various 200 gr SWC bullets to 1.250" - 1.265" OAL without feeding/chambering issues but for Sig 1911 barrel with almost no leade, same bullets loaded longer than 1.245" OAL will allow the shoulder (bearing surface) of the bullet to hit the start of rifling and prevent the finished round from fully chambering.
     

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    Last edited: May 4, 2013
  4. 918v

    918v Member

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    In any case, the L/T/F diameter is just as important as L/T/F length when the bullet ogjive is jamming at the entrance of the L/T/F. You dont want the sharp entrance of the L/T/F scraping lead off the bullet.
     
  5. Feanaro

    Feanaro Member

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    I've just started reloading and want to make sure I've got this correct. I'm working on a .45acp load with a 230gr LRN bullet. The shortest OAL that will reliably plunk in my XDs barrel is 1.622. Both of my loading manuals suggest 1.267 to 1.270 as the minimum OAL for the powders I have (Green Dot and True Blue). If I understand things correctly, I can load those up at the shorter OAL and back off the powder a bit? Start at, say, 6.2 grains instead of 6.4 and treat 7.2 grains as the maximum instead of 7.4?
     
  6. Walkalong

    Walkalong Moderator

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    Is the 1.622 number correct?
     
  7. jwrowland77

    jwrowland77 Member

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    The manual is using the OAL of 1.267-1.270 at powder charges of 6.4-7.4, correct?

    You're using a longer OAL, that fits your pistol, correct?

    I wouldn't use a lower charge than what they say in the book or your pistol might not cycle correctly. Increasing the OAL, increases the volume it can hold inside the case. Start low at minimum charge and work up and find where the sweet spot is. Make sure of the correct OAL first though.
     
  8. stavman11

    stavman11 Member

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    wow

    as always GREAT thread Guys..... learned a lot

    Thanks again
     
  9. mdi

    mdi Member

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    The question gets asked a lot because very few new reloaders take the time to research! The first time I saw the "plunk test" illustration was mebbe 11 years ago, on line...

    Excellent post Walkalong, excellent photos too...
     
  10. Feanaro

    Feanaro Member

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    It would be 1.262. Transposed a digit. S'what I get for posting after I get off a late shift.
     
  11. Walkalong

    Walkalong Moderator

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    Thought so. You'll be fine. The .45 ACP is a low pressure round with plenty of room in the case. That short change in OAL will not be a problem until you run up on max, and maybe not then.
     
  12. Feanaro

    Feanaro Member

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    That's what I thought but wanted to confirm before I blow'ded my hand off. I kinda like that hand. :)

    Thanks for this thread by the way, one of a number of useful threads on THR that have helped me with this somewhat fiddly process.
     
  13. 243winxb

    243winxb Member

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    Bump to top
     
  14. 41 Mag

    41 Mag Member

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    Vote for sticky

    Vote for sticky

    Maybe put it in the Library of Wisdom
     
  15. Jesse Heywood

    Jesse Heywood Member

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    One must not forget to engage one's brain before placing one's finger in motion. ;)

    Look in the library under plunk test.
     
  16. Armored farmer

    Armored farmer Member

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    I am new to reloading the .45acp.
    I think the info in this thread will solve my chambering issues.
    thanks
     
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