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Do I want a 20 or a 21?

Discussion in 'The SHOT ShowCase' started by DrtyHarry, Feb 9, 2010.

  1. JWP


    Apr 4, 2001
    got g21 and 2 g20s, reload both 10 and 45 and host of others, got the 6" 10mm to fit the g21 slide and it shoots well w/o changing the extractor

    ultimate goal is longslide for the 6" barrel and use it on the g 21 frame
  2. Girevik61


    Feb 2, 2010
    I'm thinking about a 20SF myself, awesome power.

  3. If you don't reload buy a GL 21 or GL 21 SF.
  4. Brian Lee

    Brian Lee Drop those nuts

    Jul 28, 2008
    Up a tree.
    Yes, yes, and yes.

    DT is one of 5 different brands I've shot and checked, and I've used the same chrono to check other calibers too - it seems to be working fine. And DT clearly states velocities from a G20, with no mention of barrel length, so I assume it's the stock barrel. My results have shown that you have to use the 6" (Glock brand) hunting barrel just to get DT ammo to go 100 to 200 FPS slower than they advertise. With the stock barrel, the velocities are even worse than that, so I don't think I'm tainting the results with improper barrel length.
  5. Brian Lee

    Brian Lee Drop those nuts

    Jul 28, 2008
    Up a tree.
    You seem to have it backwards. The G21 & G30 can be converted to 10MM, but the 10MM guns cannot be converted to .45 caliber because the breech face of the 10MM is too narrow to hold the wider .45 caliber shell.

    10MM G21 conversion barrels are available at:

    KKM and Storm Lake have them in both standard and 6" lengths, plus KKM has them for the G30, but only in the short length. Apparently Lone Wolf and Bar-Sto do not offer 10MM barrels for the G21 & 30.

    It's well known that people have done this conversion, but since the G21 & 30 breech face & extractor are really not quite right for the smaller diameter 10MM cases, the only issue is whether the reliability is as good as a stock G21 shooting .45 ammo. It's certainly been shown to work, but I was hoping somebody who has done the conversion would jump in here to let us know exactly how well it works.

    It's the exact same issue with converting .40 caliber guns to 9MM because you're changing the diameter of the ammo cases to a smaller size.

    The G20 is the king of conversion versatility because 10MM, .40 caliber, .357 Sig, and 9x25MM Dillon all have the exact same outer dimensions at the rear end of the cases, so the breech, extractor and mags are all perfect for all four calibers.
  6. MistoGators

    MistoGators 0331 - Guns Up

    Jan 29, 2010
    10mm ammo is pretty hard to find and is expensive (even here in GA). Get the slim frame Glock 21.
  7. biggin215


    Jan 21, 2010
    OOOO.... GOOD!!! That means all i need to do is drop a few bucks on a 10mm barrel and some mags and I have a 10mm???

    Another question.... Could I put a full size barrel in my G30? Like a 5inch 10mm barrel in my G30 and just have it stick out a little?
  8. Cineski


    Jun 18, 2009
    Keep in mind, the G21's breech face is bigger than the G20, so you run a risk of failure if using a G21 converted to 10mm in a defensive situation. Plus, the G20 slide is heavier than the G21, and thus it controls 10mm recoil better.
  9. AJE

    AJE Grumpy Old Man

    Apr 5, 2004
    SW Ohio
    I have a G21SF with a 6" Lone Wolf slide and a 10mm conversion barrel.

    I would not recommend this setup (yet) for a defensive gun, as it has not run 100% like my stock Glocks have. I have only put a couple of hundred rounds of 10mm through it at this point, and I'm working on developing some of my reloads with it. The chamber on the KKM is much tighter than a stock barrel which leads to possible misfeeds, especially when it's not cleaned.

    I have also read trouble people have had with the conversion barrels failing to extract. I have rarely had problems with extraction, mine has only been the rounds hanging up while feeding into the chamber. Even then, it might only be once or twice in 100 rounds, but that's still too much for a Glock!


    That said, the 10mm is absolutely a kickass cartridge!
  10. G33

    G33 Frisky! Millennium Member CLM

    May 29, 1999
    With G29
    Get 21.
    Get 20 conversion barrel.
    Get a 20 mag.
  11. Bello

    Bello America/Italia

    Sep 24, 2008
    East Coast
    do what i do.. get both.. i never use conversion barrels i just buy the gun.
  12. DrtyHarry


    Sep 26, 2007

    That is a beautiful looking pistol you have there, I was planning on getting a 6" barrel for it, and now I'm going to have a look at the LWD slides.

    For the reasons you mentioned above, I'm most certainly taking the G20 path. Like I said earlier, if I want to shoot .45, I'll grab one of my many 1911s. Thanks for posting that pic and thanks to all those who contributed here. You guys rock! Oh, and if someone can tell me when a G20sf RTF2 is due out, I'd really appreciate it. THANKS!!


  13. Preferably in olive drab for me.
  14. Iceman cHucK

    Iceman cHucK

    Jun 23, 2008
    WA state
    I have done the exact same testing of DT 10mm and 45 ammo and experienced the same results as Brian Lee. With a 6" barrel I do not get the claimed velocities of the 4.6" barrel. I like the DT ammo BUT all of mine is at least 100fps under advertised velocities. I have brought this to their attention and have gotten no reply! The Reed ammo tested seems to be right on.
  15. kcolg5150


    Oct 8, 2009
    Good question,I bought a 21sf and then wanted more bang for the buck,bought the 20 and was very impressed and it's just so different than a 45acp round. The 10mm is to much fun(more expensive) but worth it. If i had to keep one it would be the 10mm....nasty! Love it! So much I bought a 29......even more fun in a smaller's a disease.......good luck.
  16. Max1775

    Max1775 Marine Infidel

    Oct 1, 2009
    Helotes, Texas
    The G21 and G21SF are the same caliber. .45ACP. Do you mean you bought a G20?
  17. Gokyo


    Apr 24, 2005
    I own a g20

    I can I ahve barrels that allow me to shoot.
    357 sig

    Seems like a pretty cool platform.

    All I do is swap barrels, it uses the same extractor and magazines for all ammo.
  18. Bigmike75


    Jul 29, 2009
    I believe the frames are the same 20 vs 21. Why not buy a second slide and barrel for the other caliber?
  19. kcolg5150


    Oct 8, 2009
    Yes your correct,I meant 20. Just fixed.Thanks.
  20. RonaldG29

    RonaldG29 Noah's Hero

    Jan 5, 2010
    Miami, FL
    G20! all the way.