G4 Upper on G3 Lower.

Discussion in 'Glock Forum' started by j102, Jun 6, 2012.

  1. j102

    j102 Well-Known Member

    Hi All,

    I was just wondering, can a Generation 4 slide (complete upper) be installed on a Generation 3 frame (complete lower).

    It sounds like a silly question but I don't have yet any G4 glocks to compare. It's a question for those who have both and for Glock Armorers.

    Please don't break any glocks in the process.. :))
  2. dwcfastrice

    dwcfastrice Well-Known Member Lifetime Supporting Member

    From what I've read around the interwebs, If you can put it on, you cannot reliably do so for along period of time. When I was looking around for just a slide to purchase for my G23G4, there was a guy that was running a Gen 4 upper on a Gen 3 frame and because of the dual spring Recoil Spring, he was getting cracks in the gen 3 frame (or it could have been a Gen 3 upper on a Gen 4 frame- old age- can't remember now). I can't find the link now otherwise I would verify it for you.

    AFAIR, he was shooting fine, but when he broke open the gun, the RSA was bashing against the inside of the frame. Other posters on the web have stated that they haven't been able to get the Gen 4 slide to even slide on to the Gen 3 frame. So there seems to be a bit of conflicting info on the web. However, there are a lot of folks who have done side by side comparisons and it LOOKS to me as if you cannot do it due to the differences in the slide and frame.

    referencing another forum: http://www.northwestfirearms.com/general-firearm-discussion/51393-glock-gen3-gen4-observations.html The OP talks about his personal experience trying to swap G3 and G4 parts.

    not my picture:
    http://www.texasguntalk.com/forums/pics/gen4/4.jpg Gen 3 slide vs Gen 4 slides

    From what I understand, if the G3 gun had a Dual Spring RSA already, the slides are interchangeable.

    You can do a G3 Upper on a G4 lower.
    Not my picture:

    http://i4.photobucket.com/albums/y148/MrVvrroomm/Glock Gen4/IMG_1532.jpg

    Easiest thing to do is get a "complete" slide from Glockmeister/Glockstore or gunbroker that's compatible with your GEN Frame.

    Last edited: Jun 6, 2012

  3. mikecu

    mikecu New Member

    When I got my Gen 4 27, I swapped the slide with my Gen 3 and it seemed to fit the same. I didn't get a chance to take them to the range to try them out with them swapped.
  4. voyager4520

    voyager4520 New Member

    You can do it with the subcompacts. But for the full size and compact models the Gen4 upper won't even fit onto a Gen3 lower. The tang of metal on the slide which holds the muzzle end of the guide rod is wider on Gen4 slides, and Gen4 frames are accordingly wider in the dust cover. The dust cover of a Gen3 frame is not wide enough for a Gen4 slide to work on it.
  5. j102

    j102 Well-Known Member

    I am not planning on doing it. It was just out of curiosity.
    Thanks for your responses!
  6. Joflo

    Joflo New Member

    My question is, is possible to place a gen4 recoil spring assembly into a gen3 model? The goal would to reduce recoil as advertised on gen4's. has anyone attempted this?
  7. nope, the hole under the barrel isnt bid enough
  8. Joflo

    Joflo New Member

    To bad, live in California, can't get gen4's here. Was hoping to upgrade my gen3's. Thanks!
  9. Dark Knight

    Dark Knight Administrator Staff Member Admin Moderator Lifetime Supporting Member

    Where in ca do you live? Near Bay Area here
  10. Joflo

    Joflo New Member

    Live in Bakersfield. Have daughter in SF, shot at this last GSSF match in Richmond.