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9mm gain more advantage from long bbl than 40 or 45

Discussion in 'Handguns: Autoloaders' started by Dr_2_B, May 5, 2012.

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  1. Dr_2_B

    Dr_2_B Member

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    For the life of me, I can't find the post. But awhile back I recall reading that the 9mm benefits a great deal more from the length of a rifle barrel than a corresponding barrel length increase in, say, the 40 or 45.

    Can anybody point me to that info?
     
  2. MachIVshooter

    MachIVshooter Member

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    None of those gain much going from 4" or 5" to 16" or so. They all use fast powders. In my experience, .45 Auto gains the most.

    Magnum-type cartridges with larger charges of slower powder benefit more from extra barrel length. 10mm Auto, .357 Mag., .44 Mag, etc.
     
  3. TonyAngel

    TonyAngel Member

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    It's been a while, but from what I recall, the 9mm will pick up about a couple of hundred feet per second when coming out of a carbine length barrel as opposed the coming out of a 4 or 5" barrel. It isn't much, but it's something.

    I would speculate that the 9mm and .40 cal would benefit more from being shot out of a longer barrel. I say this simply because these two cartridges are typically loaded with slower burning powder when max loads (or factory duplication loads) are used.
     
  4. R.W.Dale

    R.W.Dale Member

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    The greater pressure rating and and bore case ratio of 9mm/40 gives them a better ability to gain from more barrel than the very low pressure 45acp
     
  5. 56hawk

    56hawk Member

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  6. Pigoutultra

    Pigoutultra Member

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    I guess smg's have it right with non I've seen having a barrel length of more than 10in.
     
  7. Walkalong

    Walkalong Moderator

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    It depends a lot on the powder. In general, fast powders will see little gain, and slower powders will show the most gain.

    A Hornady 115 Gr RN over 6.3 Grs of HS-6 gave me 1039 FPS form a 3" EMP, 1168 FPS from a 5" 1911, and 1330 FPS from a 16" AR. (Check data and start low)

    True Blue, AA #5, N340 etc give similar results, with N340 being the king of the 3" velocities.

    N320, 700X, etc gave very little gains in the 16" barrel.
     
  8. NMGonzo

    NMGonzo Member

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    Hit what you intend to.
     
  9. Dr_2_B

    Dr_2_B Member

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    Thanks 56Hawk. I find charts like those mesmerizing. I'll spend several minutes looking at those.
     
  10. 56hawk

    56hawk Member

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    You're welcome. I got them from this site: http://www.ballisticsbytheinch.com/ They have the raw data and tests from specific firearms also.
     
  11. MichaelK

    MichaelK Member

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    I don't yet have data for .40S&W, but I've shot .38 specials in a 6" revolver and 16" carbine using 8 grains of Blue Dot. Blue Dot is definately over on the slow side of the burning curve and I got 1090 fps and 1265 fps respectively. That's only 175 fps from an extra foot of barrel. That's the same amount of Blue Dot I load with Lee's 120 TC in 9mm.

    That data seems to correlate well with Lyman's data comparing pistol and carbine length barrels. For 9mm I believe you only got another 125 fps with a carbine barrel; nice, but not barn burning fast!

    If you really want to see increased long-barrel performance, you need to go with larger revolver cases that can handle large amounts of H110.
     
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