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Glock 20 10mm and the use of .40 S&W

Discussion in 'Caliber Corner' started by mudslinger79, Oct 20, 2012.

  1. Just picked up and nice 3rd Gen Glock 20 in trade last night. The 10mm round has always been one of those oddball rounds that I really wanted to get in to. I also acquired about 120 round of ammo with the trade. Some Federal hollow points, some Georgia Arms target round and some Prvi hollow points. :wow: Looking around online, 10mm seems to be about the same price as .45 ACP just not to easy to find around here. (Virginia) I can pick it up at gun shows with no problem.

    On to the question at hand. I was reading a thread in here that was posted a few months back. I think it answered my question but I really want to be sure. Can I run a regular old 40.S&W round through my factory Glock 10mm barrel safely??? If so then that just made my damn day!!!!!!! I would be able to save a bit o' money and buy some Underwood ammo for self defense and use the .40 S&W for target practice. :rock:

    Plus I can reload my spent .40 and 10 mm brass!!!
  2. uzimon

    uzimon team ftp

    Jul 11, 2007
    Need a conversion bbl but use same mags

  3. dkf


    Aug 6, 2010
    Yep buy a .40 conversion barrel from Storm Lake or KKM and you are set to shoot .40. The 10mm is a good reason to start reloading.
  4. PrecisionRifleman


    Jan 24, 2011
    If you reload be aware that you can't cut down 10mm casings to 40S&W size and load them. The inner dimensions are thicker in the webbing of the case head on the 40 than the 10mm casing.
  5. NEOH212

    NEOH212 Diesel Girl

    Mar 25, 2008
    North East Ohio
    No you can't without a conversion barrel.

    I didn't even read the thread but I'm guessing the answer is correct for what he probably asked.

    Last edited: Oct 21, 2012
  6. uz2bUSMC

    uz2bUSMC 10mm defender

    Oct 21, 2005
    J-Ville NC
    It has been done by a few people routinely, but it's not really a good idea. The .40 will basically just be held on to the breach face by the extractor. Your best and most safe bet would be to spend a little $ and get the conversion bbl. This will also provide you with better spent brass for reloading.
  7. shotgunred

    shotgunred local trouble maker

    Mar 1, 2008
    Washington (the state)
    It cost the exact amount to reload 10mm and 40sw.
    Why don't you check into reloading? I can reload for $100 a thousand. How much do you spend on buying a K?
  8. I do reload. I was curious about shooting a 40 cal round in a 10 mm barrel. I see what people are saying about the extractor holding it in place. I will not risk the danger. A barrel is in order!!!! Who makes a good aftermarket barrel? I have looked at Storm Lake and Lone Wolf. Are the LW barrels any good? They're prices are great, I just don't want to get one of the LW barrels and it end up being a non feeding, $100.00 paper weight.
  9. dkf


    Aug 6, 2010
    I would spend the extra money on the Storm Lake or KKM. Both American made barrels with better quality.
    Last edited: Oct 21, 2012
  10. Wil Terry

    Wil Terry

    Nov 28, 2001

    I have shot thousands of 40S&W cartridges through my old G20 10MM with nary a problem ATALL. This is not now nor ever has been any big deal either. NO IT IS NOT GONNA BREAK ANYTHING !!!

    YEP, bought a 40 BBL way back when but why bother, and it did not shoot as well as the original GLOCK 10MM BBL.
  11. SCmasterblaster

    SCmasterblaster Millennium Member

    Sep 24, 1999
    Hartford, Vermont
    I wonder if a .40 would work in a 10mm barrel? - the headspace is far different.
  12. I have a LW 10-40 conversion barrel and I have not had one problem with it. I shoot 175gr cast SWC bullets from a Lee mold.

    My experience, yours may vary.
  13. 2afreedom


    May 6, 2007
    The South
    Are you casting or using lead bullets to get to your $100/K price point? The reason I asked was I was looking at reloading components recently and couldn't see how you would get to that price, even with free brass. Thanks.
  14. SDGlock23

    SDGlock23 Glockoholic

    With free brass, lead bullets bought (casting your own would cut price big time) and the powder/primers (assuming you already had the powder at least) one could spend around $100/K. 10mm for me ain't free though, but .40 is and that's mainly what I reload for, well no I sold my 10mm so I don't even load for that now.
    Last edited: Oct 24, 2012
  15. 2afreedom


    May 6, 2007
    The South
    What would the cost be up to if you bought precast lead bullets? I'm not inclined to take up casting. Thanks.
  16. I have been reloading for 9 mm for some time now and am going to start on 40 S&W and 10 mm soon. I think for safety sake I will get a conversion barrel for 40 S&W and another for .357 Sig. I have been very interested in 357 Sig for some time and found conversion barrels for the Glock 20. I think it will be fun to have one gun chambered for 3 different rounds.
  17. Sigobsessed

    Sigobsessed Ruggedly handsome

    Jan 16, 2012
    Rochester ny
    A lot of people say its alright to shoot 40 through a 10mm but I wouldn't recommend it. The 10 mm is longer and the bullet actually sits into the rifling when chambered the 40 won't so eventually the rifling at the chamber will be damaged from the shorter round. You could do it in a pinch. But it's not recommended I would buy the conversion barrel and have the best of both worlds.
  18. That is exactly what I was worried about. I really don't want to damage a perfectly good barrel.
  19. AKRover

    AKRover 10MM Fanatic

    Jun 22, 2012
    Kenai, Alaska
    If you're going to reload save yourself the cost of a 40 conversion barrel and just load lighter 10mm loads
  20. SCmasterblaster

    SCmasterblaster Millennium Member

    Sep 24, 1999
    Hartford, Vermont
    That's right. Most 10mm factory loads these days are on the lighter side - more like .40S&W anyway.