Privacy guaranteed - Your email is not shared with anyone.

Welcome to Glock Forum at

Why should YOU join our forums?

  • Reason #1
  • Reason #2
  • Reason #3

Site Description

.40>9mm conversion questions

Discussion in 'General Glocking' started by Rottizine, Aug 17, 2012.

  1. Rottizine


    Aug 5, 2012
    New to glocks, so bare with my noobiness :supergrin:

    Contemplating buying a used G27 gen 3 and a lone wolf 9mm conversion barrel.

    1) Is there any problems when going from one generation of magazines to another? ex. G17gen2 or gen4 mags into a G27 gen 3 gun? G18 high capacity mags in a G27?

    2) Can you use the .40mm mags for the 9mm rounds?

    3) any other minor problems or things to consider when buying parts for a setup like this?

    Thanks for everyone's time
  2. larson1122


    Jan 30, 2012
    1. All Generation 1,2,3,4 magazines will work fine in your Gen 3 G27, including the G18 mags. The only time the generation of the magazine matters is when using a Gen 4 pistol with the magazine catch reversed for left handed operation, which would require a Gen 4 Magazine.

    2. Yes. I've seen quite a few reports of people shooting 9mm out of a .40 S&W magazine without issue, but a lot of people like to buy dedicated 9mm magazines to use with the conversion barrel.

    3. Barrel and maybe magazines are all you should need. Some people switch out the extractor and ejector when using the conversion barrel but this usually isn't necessary unless you have issues with it or are planing to use this conversion setup for self defense purposes. (Conversion barrels for self defense is a topic for a whole new thread and you will see strongly opinionated posts both for and against this.)

    Good luck! :wavey:

  3. barth

    barth six barrels

    Oct 7, 2011
    The Free Zone
    Do yourself a favor and get 9mm mags for your 9mm barrel.
    Last edited: Aug 17, 2012
  4. ChicagoZman


    Jun 29, 2010
    Have a couple of 40/9 conversion barrels I use for fun in my 24 and one of my 22s. While I used to swap extractors and ejectors when converting, I no longer do so as I have had zero issues using the .40 parts with the 9mm barrel. However I do use 9mm magazines as I own many of these.

    Good luck.
  5. barth

    barth six barrels

    Oct 7, 2011
    The Free Zone
    Have G23 and G27 Storm Lake 40-9mm barrels for my Gen 3 G27.
    1000+ rounds of flawless 9mm with the 40 extractor/ejector with no BTF.
    Strongly recommend you just go with 9mm barrel and mags.

    Plus if you change to 9mm ejector/extractor,
    you can't easily change back to 40/357 with just barrel and mag swaps.

    I use 124/127 gr full power 9mm.
    Last edited: Aug 17, 2012
  6. SGT278ACR

    SGT278ACR Retired Veteran

    Nov 12, 2011
    16S DE 680 928
    Yep. All the above info is good. I don't change anything, but the barrel and mags in my G22. I've also heard others continue to use the .40 mags with 9mm ammo, but I just get a better warm & fuzzy using 9mm mags.
  7. arushus

    arushus Biggest Member

    Jul 22, 2011
    NE Oklahoma
    Ive got that setup. A G27 with 9mm stormlake conversion. I highly recommend you get the 9mm magazines. Bo*tach tactical has them for $22 right now, but if you enter coupon code "mags2012" you get a 10% discount on them...

    I had to exchange out my .40extractor for a 9mm extractor because I was having issues with the original extractor not pulling the 9mm cases out of the chamber every now and then. The 9mm extractor has worked without failure for both 9mm rounds AND .40sw rounds!
  8. off topic but I asked my LGS if they sold conversion barrels from 9 to .40, guy looked very confused and then told me that the 9 and 40 glocks were different sizes and if you put a 9 mag in a .40 gun it would rattle around, I clarified that I said and meant .40 to 9, not .45 or 10mm to 9 or 40 or .357 sig.I thanked him for his "help" and left, its not even worth correcting those guys. Its disconcerting knowing new gunners look to them as authorities