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40 and 10

Discussion in 'Reloading' started by Ski2me, Dec 15, 2012.

  1. Ski2me

    Ski2me Glock Envy

    88
    0
    Apr 11, 2012
    SE Idaho
    What should I expect if I load my 10mm rounds with the same amount of powder and same bullets as I use in my 40 S&W loads? Of course I'd be using large pistol primers and the longer 10mm OAL. I don't have a chrony so I'd like info on how they would compare.
     
  2. dkf

    dkf

    5,472
    150
    Aug 6, 2010
    There a good bit more case capacity with the 10mm. So a .40 powder charge and bullet in a 10mm case will most likely yield lower velocity than in the .40 case.

    Take a look at some of the starting loads for 10mm with the powder you are using in .40 and see how much difference there is.
     

  3. HAMMERHEAD

    HAMMERHEAD

    3,449
    20
    Dec 20, 2002
    Minnesota
    You will loose about 100 fps, or at least I did with 165 grain bullets and Universal.
     
  4. countrygun

    countrygun

    17,069
    18
    Mar 9, 2012

    I agree. The actual difference depends upon the powder depends on the powder.
     
  5. copo9560

    copo9560

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    Feb 21, 2012
    Why not just use 40 S&W cases and load data. They fire just fine in a Glock 20/29 even though they are kind of short.
     
  6. dkf

    dkf

    5,472
    150
    Aug 6, 2010
    Th e10mm headspaces of the case mouth so if you fire .40 in a 10mm barrel you are depending on the extractor to keep the round where it should be. It may work but it is far from ideal and can have negative consequences.
     
  7. Ski2me

    Ski2me Glock Envy

    88
    0
    Apr 11, 2012
    SE Idaho
    I have been using 5.5gr of WST with 165gr plated RNFP in my Glock 22. I'd like to use the same components in my new Glock 20 for the sake of convenience. Just curious how the added cartridge space affects performance.
     
  8. dkf

    dkf

    5,472
    150
    Aug 6, 2010
    Handloads.com has a 170gr JHP load listed with 5.5gr of WST @ 1020 fps 29,500psi but I do not know what gun it was tested in. The start load was listed as 5.0gr. The 170jhp bullet close to what a 165gr plated would be because lead data is usually a little more conservative. I would start below 5.5gr for safety sake and work your way up. If you could find other load data it would be a good idea also, although I do not think you are going to have issues at all.
     
    Last edited: Dec 15, 2012
  9. fredj338

    fredj338

    22,637
    1,435
    Dec 22, 2004
    so.cal.
    As noted, you'll lose about 100fps vel using 40 loads in the longer 10mm. Kind fo no point really, the 10mm is a race horse not plow horse. Might as well just shoot the 40.:dunno:
     
  10. Ski2me

    Ski2me Glock Envy

    88
    0
    Apr 11, 2012
    SE Idaho
    Thanks for everyone's help. For those wondering why I'm wanting to load a G20 so light. I want the power of the 10mm for protection from critters when I'm on my ranch. I'll use Buffalo Bore for that. But I want the convenience of easy reloading and shooting for everything else.

    Thanks again everyone.