Can I convert my G21 to shoot 10mm?

Discussion in 'General Glocking' started by Speedemon415, Jan 23, 2010.

  1. Speedemon415

    Speedemon415

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    HI all,

    What do I need to do to my G21 to be able to shoot 10mm rounds?
     
  2. jaybirdjtt

    jaybirdjtt

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  3. Speedemon415

    Speedemon415

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    Thanks! So all I need to do is get a new barrel?
     
  4. G33

    G33 Frisky! CLM Millennium Member

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  5. 21Glock

    21Glock

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    Is this only with KKM barrels or can I put in a Glock 20 Lone Wolf barrel and a stock 10mm magazine to turn my Glock 21SF into a 10mm shooter, as well?

    Thanks.
     
  6. 21Glock

    21Glock

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    Will the KKM or Lone Wolf 10mm barrel work OK with the stock 21 slide?
    Thanks.
     
  7. bentbiker

    bentbiker

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    KKM labels them as "drop-in".
     
  8. Speedemon415

    Speedemon415

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    From what I've seen on GT we do not need to change the slide at all. There is some debate on whether to use the conversion barrel KKM makes or just use an OEM Glock 20 barrel in the G21. Can anyone with experience on this conversion chime in?
     
  9. 21Glock

    21Glock

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    I have a 21SF and I plan on adding 22lb. springs and a SS T.H.E. guide rod to my 21SF,so I should be OK. Will the 21SF slide extract the 10mm rounds OK as is?
     
  10. muad

    muad Lifetime Member

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    I asked a similar question about my G30, and using aG29 barrel and magazines. Never really got any solid info. From what I've read, the kkm and LW conversion drop-in barrels are the way to go.

    It would be nice to know if you can just swap in the factory 10mm barrels into the 21/30.
     
  11. Gabby

    Gabby

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    Have swapped a 29 barrel into a 30, inserted a 29 magazine and it worked fine. The 29 barrel was stock Glock.

    It works for a 20 barrel and magazine in a 21 as well.

    Extractor profiles may be a bit different. Even so, the functioning was flawless for me.
     
  12. Desertscout

    Desertscout CLM Millennium Member

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    Gabby is exactly correct. I have have done both combinations with stock 10mm bbls and have not had any issues. As Gabby said, IF, big IF, you have any problems, it will most likely be due to the extractor.
     
  13. AustinTx

    AustinTx

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    Is the OD of a G20 barrel the same as a G21 barrel? I didn't see that anywhere.
     
  14. 21Glock

    21Glock

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    Worse comes to worse, Lone Wolf sells extractors for the 10mm. I could change those out and be good to go. I believe the plunger, firing(striker) pin and everything else is the same.
    I have e-mails into KKM and Lone Wolf on this subject and will let everyone know their response.
    Thanks.
     
  15. muad

    muad Lifetime Member

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    Gabby,

    Thanks for the insight. Now all I need to do it get a G29 barrel and some mags :)

    Do you think upgrading the springs on the guide rod is necessary if I plan on using this combo often?
     
  16. 21Glock

    21Glock

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    I talked to the fine folks at KKM this afternoon and they said it should work, but in 50% of the time there are extractor issues with the difference in the 10mm rim and the .45ACP. He said to thin down the extractor if that happens and it should be OK after that with firing the 10mm in the 21 slide.
     
  17. RayB

    RayB Retired Member

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    I neither hunt nor fish, and since I don't reload, and since 10 mm is a bit of a unicorn in my area, I couldn't find a used G20,, nor justify the cost of a new G20/G29. But I wanted to dabble in 10 mm!

    As for just swapping out barrels, if it works, it works, I guess. But I went the Caliber Conversion Barrel route.

    A Caliber Conversion Barrel combines the outside specifications of the gun's original caliber with the inside specifications of the substitute caliber. If the two caliber's footprints are similar enough, this can work very well. :thumbsup:

    The G20's slide is heavier than the G21's. The extra metal in the G20's slide is well ahead of the firing chamber, so it's an inertial/mass thingy--a concession to the more powerful 10 mm cartridge. This can be somewhat offset with a heavier recoil spring.

    When you consider the available loadings of today's ammos, bullet weights, pressures, and plus pressures, we're clearly looking at an operational range, rather than a specific formula. :headscratch:

    I accomplished my G21's conversion to 10 mm with the following...

    - KKM .45 - 10 mm Conversion Barrel
    - ISMI 22 lb. Recoil Spring
    - LWD SS Captive Guide Rod
    - Glock OEM 10 mm Magazine(s)

    The KKM Barrel features a fully supported chamber and can handle naked lead bullets. FWIW, the stainless steel barrel looks cool on the gun! :cool:

    It was necessary to play with ammo types to get to acceptable reliability. I found that the square-nosed, naked lead bullets did not load reliably up the conversion barrel's slightly steeper feed ramp. Most of the bulbous-nosed cartridges, hollow point or otherwise, load just fine.

    I like the hot loads! I mean, otherwise, what's the point? :dunno:

    My favorite ammo is Double Tap. My favorite cartridge is the sizzling 135 gr, 1600 fps, 767/ft lbs, Nosler! This is true .357 magnum power! :wow:

    This conversion is maybe 99% reliable. I do get the occasional misfeed every now and then, but some range sessions are flawless. I might try a 20 lb. spring one day, and see if that gets me to 100%. At any rate, this is fine for range play.

    The accuracy is fine. I can nearly duplicate my G21's performance in .45 mode with this rig. If I shot more ten, this would no doubt improve.

    In all, the conversion project ran about 1/2 the price of a new G20, all costs considered (including taxes and fees saved).

    While I would recommend a dedicated 10 mm for woods or carry, the conversion approach works fine for those that just want to experience and dabble in the impressive ten.

    --Ray
     
    Last edited: Jan 25, 2010
  18. 21Glock

    21Glock

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    Hey, way to go Ray B. Did you leave the 21 extractor intact?
    KKM mentioned to me today that the only possible hiccups with running 10mm in the 21 slide would be that the extractor might not be thin enough to grap the 10mm rim and could be filed down somewhat to make it work right.
    Looks like your set up is smokin' ! It's funny I wanted a 20 when I got my 21SF, the 20s were hard to find when i shop. I guess I'll get my wish after all.
    Thanks for the info.
     
  19. Gabby

    Gabby

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    I was told by someone that KNOWS Glocks inside and out that the innards of a 29 and 30, other than the barrels, mags, and MAYBE the extractors are the same. No need to change springs. I think with a 29 barrel and mags, you will be good to go with sucessfully converting your 30 to a part-time 29. At 7 yards or so, the point of aim, for me, didn't change between 30 and 29 configuration.
     
    Last edited: Jan 25, 2010
  20. 21Glock

    21Glock

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    I just down and tried some 10mm rounds that I bought some time ago with how they mated with the extractor on the 21 slide, looks like it will work OK from what I can tell.
    I'll be getting the KKM 10mm conversion barrel soon. Picking up some 15 round mags. at the next gun show. Yeah!!!