Glock 21 .45 ACP convertible to a 10 MM?

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  • Kobiash1

    Active Member
    Rating - 100%
    4   0   0
    Oct 20, 2013
    little elm
    Is a glock 21 .45 ACP convertible to a 10 MM , like a Sig .357 to .40 cal. ?


    Lifetime Member
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    14   0   0
    Oct 15, 2009
    Lampasas, Texas
    Yes on three pin frames. The two pin frames will apparently not handle the extra recoil.

    You will need a conversion barrel not a standard G20 barrel though. The exterior dimensions are different from a factory G21 and G20 barrel. You will also need G20 mags. G21 mags will not work.

    By the time you buy the parts you are half way to buying a G20. I would just buy get a G20 personally.

    BTW, I haven't done this conversion. I have just read about it. I suggest you Google it and become familiar with what it takes before you proceed.


    Active Member
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    3   0   0
    Jan 9, 2009
    Round Rock
    This has been discussed on another forum. Reportedly one maker is marketing "conversion" barrels for this swap. I for one would not trust this as the difference between the .45 ACP base diameter and the 10mm base diameter is MUCH larger than the difference between the .40 and 9mm. .40 to 9 with the same extractor? Sure. Heck the .40 shell holder on must reloaders is adequate for 9mm (adequate, not ideal). Try using a .45 shell holder to size 10mm? You will get a bunch of ripped off rims.

    If you want to shoot 10mm out of a G21, buy a different top end.
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