.40 Chamber Support: Gen 4 vs. Gen 3?

Discussion in 'General Glocking' started by Matt VDW, Sep 26, 2018.

  1. Matt VDW

    Matt VDW Millennium Member

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    Do the Gen 4 Glocks in 40 S&W have better chamber support than the Gen 3 Glocks?

    I know that the older pistols have "enough" support, but for handloading purposes I'd like to minimize the amount of case bulge I have to remove.

    What would you do with a Glock 27 Gen 3 with a loose chamber? Put a Gen 4 or aftermarket barrel in it, or upgrade the whole thing to a Gen 4? Or wait to see if there will be Glock 27 Gen 5?
     
  2. Mike-M

    Mike-M

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    OEM Glock 40SW barrels saw significant improvement in cartridge case chamber support from 1990 through the early 2000s.

    There are no Gen3 versus Gen4 40SW barrels. However, barrels in Gen4 pistols are 2010 or later, and will have better chamber support than the barrel in a 1998 Gen3 pistol. But so would a 2010 Gen3 pistol. Improvement was made by production date, not generation.

    The photo below compares three of my Glock barrels. (Click for larger photo.)
    [​IMG]
    Left is a 1996 40SW chamber.
    Center is a 2012 40SW chanber.
    Right is a 2011 357SIG chamber.

    Note that the 357SIG chamber because of the case bottleneck is tight and has perfect and complete chamber support even above the feed ramp. It is the best of all OEM calibers in these characteristics.

    When I upgraded my 1996 Gen2.5 G27 six years ago, I was making a similar choice in order to get rid of occasional Glock Grins on the cartridge cases from the original barrel: Use a new OEM 40SW barrel...or use a new OEM 357SIG barrel. I chose the latter, and have been most happy with my Gen2.5 G27/33 for EDC. With Underwood 125-gr JHP 357SIG ammo it produces MV=1410 fps, ME=552 ft•lbf, PF=176.
     

  3. thewoods868

    thewoods868 thewoods868

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    Which hollow points gold dots or nosler from underwood do you use?
     
  4. WeeWilly

    WeeWilly

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    It doesn't make any difference in performance if the loads your are shooting are within SAAMI specs. If you are reloading and pushing pressures above published maximum, more chamber support can help stemming the onset of smiles in your cases.
     
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  5. Matt VDW

    Matt VDW Millennium Member

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    Thanks, Mike-M. That was a very helpful and informative post.