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9mm case bulge question

Discussion in 'Handloading and Reloading' started by distra, Apr 29, 2008.

  1. distra

    distra Well-Known Member

    I've been loading 9mm for a while now and everything has been running through my BHP and XD9 just fine. I picked up a G19 a couple weeks ago and have a few rounds jam in the chamber. I pulled them out and measured the OAL (1.071"), crimp, and base diameter (0.393") and compared those to rounds that have been working in the G19, OAL (1.075"), crimp, and base diameter (0.385"). My loading manual says based diameter should not be above 0.391" however, the BD=0.393" rounds fit and function in my BHP. :confused: Is it just the difference in the chambers between BHP and G19 or have these cases just had all they can take? I was always under the impression that Glocks had loose chambers and would eat anything, I guess I'll have to rethink that.
  2. Grandpa Shooter

    Grandpa Shooter Well-Known Member

    Depends on the barrel, not the make of gun. What is the diameter of the chamber of the guns you own? You will likely find that the Glock has tighter tolerances that you thought. You don't mention if you bought it used or new, but it may have a match barrel.
  3. strat81

    strat81 Well-Known Member

    Describe the jam.
  4. distra

    distra Well-Known Member

    I bought the it used and the barrel + slide have the same serial number on it. I have not measured the chambers yet, but that's a good idea. The jams are such that the round will only go part way into the chamber resulting in the slide not returning to battery. Then the only way to clear it is to put the edge of the slide in contact with the edge of the shooting bench then push the grip down towards the ground with some force. I've had a couple that I had to just shoot out because I could not rack the slide to get the round out.
  5. rcmodel

    rcmodel Member in memoriam

    If the base in front of the rim still measures .393" after sizing, you aren't sizing them enough.

    Screw the sizing die down until it bumps the shell holder and try that.

    PS: Take the barrel out of the Glock and use it to "chamber check" your resized brass before you bell & deprime them. If they won't fit then, it ain't gonna get any better with the bullets & power in them.

  6. distra

    distra Well-Known Member

    rcmodel, DOH! :banghead: Good catch, I didn't even think to check that. I screwed it down until it touched the shell plate then resized a couple empties that measured 0.392+" at the base and sure enough it's back to ~0.386". I used the barrel lastnight as a case gauge and had 24 out of 200 that didn't fit and separated those from my "Glock" ammo. ;) Thanks for pointing out where I screwed up! :eek:
  7. Walkalong

    Walkalong Moderator

    .391 is what the SAMMI minimum supposedly is for the case head on 9MM. (Hornady guy told me that) I have an EMP that will flat lock up with a case that measures .3915. Those same cases, and bigger still, will run through all my other 9MM guns, but I now gauge every sized 9MM brass and toss the ones that will not fall in and out of the gauge into my scrap box.
  8. jlbraun

    jlbraun Well-Known Member

    Ah, the "Glock Bulge". The Glocks have wide-throated chambers to enhance feeding. However, this means that the cases will develop a "bulge" that will lock other guns up solid if it's not resized.

    I heard that you need a stout full length resize to reload cases shot in a Glock.
  9. Jumping Frog

    Jumping Frog Well-Known Member

    Pull the barrel from your Glock. Do the cartridges drop in? If not, they are probably not to SAMMI spec.

    One advantage of the Lee 4 die set is that Die 3 seats the bullet and then Die 4 will both crimp it and post-size the case to SAMMI specs.

    As people have mentioned, it is not uncommon for Glock barrels to cause cartridge cases to develop a bulge where the case is unsupported.
  10. evan price

    evan price Well-Known Member

    Well, yes and no. You need to full length resize, yes, but I do it in my Lee Pro1K and don't even notice a difference between Glocked and Nonglocked brass. I don't even separate them. No problems with any of my 9's.
  11. rcmodel

    rcmodel Member in memoriam


    A sizing die doesn't care whether or not a case has been fired in a Glock, or anything else.

    Once you re-size it, it is back to factory dimensions again.

    Anyway, distra's problem was not that his Glock brass wouldn't fit in his other guns.
    It was that it wouldn't fit in his Glock!

    Apparently it worked just fine in his BHP and XD9.

  12. CZ57

    CZ57 member

    Just a reminder, but the accurate location to measure the casehead on the 9 X 19mm is .200" above the rim.;)
  13. distra

    distra Well-Known Member

    That's what us country folk call "a hair" above the rim :D
  14. CZ57

    CZ57 member

    A hair or two.;)

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