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Glock 10mm to .40 S&W Conversion

Discussion in 'Handguns: Autoloaders' started by Fiero, Sep 28, 2004.

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  1. Fiero

    Fiero Member

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    I am looking to convert my Glock model 20 10mm to .40 S&W.

    I've looked everywhere for any details on this matter and all I have found is a myriad of sellers of conversion barrels, but nothing else.

    No instructions, no magazine reccomendations, nothing.


    Anyone know of any details on the subject?

    I've heard that the 10mm mags will work, but will .40 S&W mags work better???

    It would seem that using 10mm mags would allow a lot of fore-aft play.

    Last question... Is the reliability the same as stock? I mean, can I trust my life to the conversion relative to unconverted?

    Thanks for any help.
     
  2. ENC

    ENC Member

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    No offense but why are you wanting to do it?

    If it will be permanent just trade for a .40

    Most factory ammo is loaded down to the same spec's as a .40.

    AFAIK all you need is the new bbl and maybe mags but I don't see them as being absolutly necessary.

    I have an HK that is convertible BW 40 and .357 and all I need to do is swap bbls.


    Going from ten to .40 might also need a recoil spring.
     
  3. SoCalGeek

    SoCalGeek Member

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    I believe the way to go would be to (check on this first obviously, as i'm not sure) replace the whole slide/barrel assembly with that of a G22. I'd also change the mags just to be safe, but that's just me...
     
  4. 49hudson

    49hudson Member

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    All you need is a 40S&W barrel.
    Glock model 22 is a smaller frame,so it's magazines won't work.
    Glock model 20 can also be converted to 357sig with just a barrel change. Just be sure to seat the ammo all the way back to the rear of the magazine and it will function just as well as 10mm ammo does.
    I have a Glock model 20C, with 6" hunting barrel and 40S&W and 357sig barrels and have never had a failure of any kind.
    Can you trust your life on a 10mm converted to another caliber? That's up to you !
     
  5. JNewell

    JNewell Member

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    I've done this very successfully. The "why?" question is worth asking, though.

    I did it because I can buy .40 Short & Weak ammo for half the cost of 10mm or less, so it can be an attractive practice setup, at least part time.

    All you need is the appropriate conversion barrel. The mags feed fine and in any case you can't use the shallower .40 mags in the 10mm/.45 frames.

    I've never had a reliability problem, and I run the G29 with a slightly stiffer recoil spring. Have never had a failure to feed or any other type of failure.

    As far as "trust my life" (your life, that is), yeah, probably, but why?:confused:
     
  6. treeprof

    treeprof Member

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    I have a KKM .40 for my G20. It functions fine with all fmj ammo, plus Rem Golden Saber, Speer GD and Win SXT; I'd trust any of those for defense. I had some feeding probs with some old PMC Starfire ammo I was shooting up just to be rid of it, but nothing else. I'm not even all that careful to seat all the .40 rounds as far back as possible. I use a 22 lb recoil spring with all of them.
     
  7. WhoKnowsWho

    WhoKnowsWho Member

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    The KKM conversion barrel is $165 at www.lonewolfdist.com

    Why not just pick up a turret press and start reloading for that amount of money? You could load the 10mm light or powerful if you want.
     
  8. Fiero

    Fiero Member

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    Thanks Guys.

    For those of you who asked why.

    1. .40 caliber S&W is cheaper
    2. The variety of ammo is greater(local)
    4. The range that is closest to me will not even let me shoot hollowpoints, which is the only 10 mm ammo at the local Turners(gun shop).
    5. I don't want to get into reloading.
    6. I have hi-cap mags for my glock 20, which are legal in PRK, because I had them BEFORE the CALI ban.
    7. If I buy a new Glock in 40 S&W, then it will have to be all lo-cap mag equipped.
    8. It's cheaper to convert, than to buy a new gun anyway.


    49Hudson brings up a good point agains the conversion though. I don't want to have to rely on a good "seating in the rear of the mag" to function correctly. What if I holster the weapon, and the ammo shifts forward in the mag? I guest I then have an unreliable jammer to protect my life with, eh?
     
  9. treeprof

    treeprof Member

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    That's not my experience, but you'll have to test your preferred ammo on your gun to be sure. Why not carry 10mm, tho, as long as HP's are available, and use the .40 primarily for practice?
     
  10. PO2Hammer

    PO2Hammer Member

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    I highly recomend the KKM conversion barrel.
    I have run several thousand rounds of .40s&w through my Glock 20. No problems. I've staggered the rounds front to back, all forward, weak hand only with a 20 pound recoil spring, no failures of any kind. Slide locks back as well. Only 10mm mags will work. No need to buy anything other than the conversion barrel.
    The Glock 20 10mm/.40s&w combo is my favorite firearm ever. With Blazer Brass 180 fmj (.40s&w), I'm getting match grade accuracy (thanks to Heinie sights) and buttery soft recoil. I've also shot this combo in IDPA and improved on my Glock 34 9mm scores (qualifiers).
    Stoked with 16 rounds of 10mm Wichester Silvertips, I feel just fine about home defense.
    If I could only use .40s&w, I would have evry confidence in my 20. Hot .40s&w ammo is a real hoot to shoot (!) in the Glock 20. Corbon 135's are awesome and there is no snap when fired in the big 20. In a Glock 35, they can be 'stingy'.
     
  11. agtman

    agtman Member

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    I've got Federal Arms' drop-in .40 barrel for my G20 - and that's all I've needed.

    The G20's stock recoil assembly and the stock 10mm mags (15rd & 10rd) work just fine with the .40 cartridge. The FA .40 barrel exhibits pretty good accuracy too (for a .40S&W anyway).

    For the aftermarket drop-in barrels for the G20 in other calibers (e.g., .40, .357Sig & 9x25), some like KKM, Bar-Sto or Jarvis.
     
  12. Clark

    Clark Member

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    I have a Glock20 10mm and I am looking for a 40sw barrel for it.

    Per my experiments, 40sw can be loaded to a higher velocity than 10mm, because of the large primer pocket is the weak spot.
    A 10mm chambered for 40sw would be the best of all worlds, seating the 200 gr bullets long for the 10mm magazine, the hevier slide taking up more recoil, and the higher pressure 40sw brass.
     
  13. JohnKSa

    JohnKSa Member

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    Clark,

    You GOTTA post more background information when you make a statement like that. Not everyone knows you blow up guns for fun...

    BTW, if you're interested in an unfired FAC aftermarket .40 S&W SS conversion barrel for the Glock 20 pm me.
     
  14. JNewell

    JNewell Member

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    Nor mine, but I've never tried shooting anything but cheap .40 ammo in my 29.

    I'm half embarrassed to admit it, but in light of my goal (cheap practice ammo, therefore need as little investment in the barrel as possible to amortize with the difference), I went with a FAC barrel. I'd have to say that it way outperforms my expectations on both accuracy and reliability (again, though, only tested with ball range ammo).
     
  15. Zak Smith

    Zak Smith Moderator Emeritus

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    The standard gun for "Limited" class in USPSA/IPSC is a double-stack 40SW on a SV/STI 1911 platform. Since this action is long enough for 38Supe or 45ACP, we have the fore/aft play issue.

    The solution most of us use is to just load long. My SV will chamber and feed rounds out to 1.230", which is probably longer than what your Glock will accept.

    If you have a 40SW barrel for your pistol with a long enough throat, you could do the same.

    Or just handload 10mm. Modulot the brass cost, it'll cost the same as loading 40SW.

    -z
     
  16. agtman

    agtman Member

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    "*** 40sw can be loaded to a higher velocity than 10mm, because of the large primer pocket is the weak spot."


    :rolleyes:

    Well, let's see. Case length: 40S&W = .850; 10mm AUTO = .992.

    Hmmm, ... guess that's what's called a KABOOM! - right?
     
  17. Zak Smith

    Zak Smith Moderator Emeritus

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    Case length isn't the real issue; it's the loaded cartridge OAL.

    I.e. what's the difference between a 40SW loaded to 1.200" and a 10mm loaded to 1.200"?

    The 10mm will actually have more initial friction because the case has more contact with the bullet.

    -z
     
  18. Clark

    Clark Member

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    This is a picture of some 30-30 brass I cut down and shot in a stock Glock 20 10mm barrel. Because the brass is thicker, a higher pressure can be reached before the brass fails, and so produce higher velocities than ordinary 10mm brass in that barrel. But becuase the internal volume is less, 40 sw brass can reach higher velocities at with a barrel with good case support.

    [​IMG]
     
  19. NorCalFlyer

    NorCalFlyer Member

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    Glock 29 to 40 S&W conversion

    I have found a couple of conversion barrels... the Fire Dragon (ported) and some others. I am wondering about the reliablity of each, so if anyone has these or has heard of any issues I would like to know which ones not to purchase.
    Thanks.
     
  20. envonge

    envonge member

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    Can someone link me to some good conversion barrels for the Glock 20 in the following calibers:

    .40 S&W, .357 SIG, 9x25

    Thanks!
     
  21. Vitamin G

    Vitamin G Member

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    Huh????
     
  22. Clark

    Clark Member

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    Yeah!!
     
  23. medmo

    medmo Member

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    Clark,

    What pressures are you running?
     
  24. GARY1911A1

    GARY1911A1 Member

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    I would guess if one had feeding problems of .40 in a Glock 10MM Magazine a spacer in the back like used on 9MM and .40 1911 magazines might solve the problem. A sheet of plastic of the correct thickness cut to the inner deminsions of the rear where the number holes are might work. You couldn't see how many rounds unless you cut holes for them too. I say try .40 in the 10MM Glock Magazine first.
     
  25. the pistolero

    the pistolero Member

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    For something like 10mm, it really would be your best option, though, and you'd also be able to shoot more in your other calibers as well. And it's not hard...it just gets addicting. :D
     
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