The Cleaning of the Glock

Did what I should have done last night, and broke down the Glock to clean and lube it, and went beyond my usual field-strip, toothbrush the slide assembly and snake the bore, drop a little lube and call it done. (Given that the usual advice seems to be to break down the slide assembly for cleaning every 3K rounds or so, I don’t think I was being that neglectful).

Took apart the slide assembly. The firing pin was pretty clean (I mean, it left some dirt behind when I wiped it down, but nothing bigger than some dust), and most of the rest of the slide assembly was the same. The extractor, though, had collected a bunch of gritty-looking nastiness, and the firing pin safety had a small collection of its own. Didn’t appear to prevent function (I never had any failures to extract), but I cleaned it all up anyway. Found an empty rattling around the safe in the process, (from a previous range session, I didn’t have any open containers with me at the firing line this time, and there was no brass in my pocket either), and compared the striker impact to the photos of the duds, and the empty was definitely a center hit and showed a faint rectangular outline around the main impact point, so whoever it was that had “light off-center strikes” in the pool wins a no-prize. It’ll probably be a couple of weeks before I can make it out to the range again to test-fire (and make sure I got the extractor in right).

I’d say “why only those three rounds,” but the answer is probably somewhere around “tolerance stacking.”

18 Responses to “The Cleaning of the Glock”

  1. Ian Argent says:

    The manual that came with the pistol only goes as far as field-strip and lube in the preventative maintenance section, so that’s why I didn’t do it before…

  2. Sebastian says:

    I don’t think you reload, but sometimes a good test if you can’t get to the range right away is to put in an empty piece of brass, but with a live primer and test fire it. I’ll let you know at least that everything is well with the parts that make it go bang. The primer will still make a bang, like a cap gun, but it will let you know.

    • Ian Argent says:

      I don’t reload, and have no plans to take up the practice. I did place the empty case I found in the chamber and racked the slide, and the empty did extract, so there is that.

      The guide to disassembling the slide assembly I found said to shake the re-assembled slide and listen for the firing pin assembly to rattle in the channel (which it did). Everything appears visually correct as well, including the Loaded Chamber Indicator part of the extractor standing proud of the slide when the empty was in.

  3. Philbert says:

    Did you see if the firing pin was still properly mobile when the firing pin safety was depressed? One of the function tests in the Glock manual is to depress the firing pin safety and then shake the slide, to ensure that the firing pin moves freely.

    I’m just wondering if there was any clue that further disassembly and cleaning was needed.

    • Ian Argent says:

      It now passes that test. Whether it did before, I know not. At any rate, the firing pin channel couldn’t have been too badly gunked up, since it functioned without issue for another 20-odd rounds after the last of the FTFs.

  4. Jeff O says:

    Sounds like you’re back to 100%. I guess I should have used a better term; maybe compounding tolerances of various mechanical systems? As engineers we usually don’t care about compounding safety factors unless its needs to break free of gravity!

    • Ian Argent says:

      I got “tolerance stacking” off Tam a while back; it seemed a rather appropriate way to describe how your total system tolerance can be the sum of each individual parts’ tolerances.

      I can’t say I’m at 100%, no way to full function test without at least a 45 minute drive to get to a range, and that’s not feasible until next weekend at the earliest. The slide racks, the ejector ejects, and the trigger pulls and resets. All the parts that were inside the pistol before I took it apart are back inside, and approximately where I found them.

  5. Zermoid says:

    Perhaps a stupid question, but did you inspect the firing pin it’s self for wear? Just wondering if the tip might be worn or chipped, every glock fired casing I’ve ever seen has that distinctive rectangular dent in the primer.
    And could the safety being dirty have slowed the firing pin down a little? (I don’t own a glock so not sure exactly how that safety works)

    • Ian Argent says:

      The firing pin on a glock is vaguely triangular in profile, it almost looks like a philips-head screwdriver that’s had 2 of the 4 lobes shaved off.

      The firing pin safety is a spring-loaded pin with a dumbbell profile. As far as I can tell, at rest, the larger diameter part of the pin prevents the firing pin itself from travelling. When the safety switch on the trigger is engaged, the firing pin safety is pushed up so that the thinner part of the assembly lines up with the firing pin, allowing the firing pin itself to travel forward. Google image search will give you fairly decent pics of the parts. While I took pictures of mine, they were in bad lighting with a cell-phone camera (my “good” camera is laid up after I busted the SD card adapter’s write-protect tab, and I’m not that good a photog anyway)

    • Ian Argent says:

      I did inspect the pin while I had it out and it didn’t appear to be particularly worn or out of true

  6. Nick says:

    I’m a longtime reloader and USPSA competitor using the Glock platform. Generally speaking when I’ve seen off center primer hits, that’s been an indication of a worn recoil spring. There’s a simple way to test for that…..

    With an unloaded gun — no ammo in the vicinity, mag out, chamber checked both visually and by touch — point the muzzle in a safe direction and pull and PIN the trigger to the rear.

    Now — slowly hand cycle the slide to check if it hangs up before fully returning to battery, all while keeping the trigger pinned to the rear. Does the gun lock up in battery? You can also point the muzzle vertically and repeat the test. If it fails either test, I replace the recoil spring assembly…..

    The other thing to consider with the 17L is that there’s a bit more mass in the slide, but the recoil spring assembly is identical to the one used in the 17. That means that everything needs to work a little more perfectly on the 17L to ensure reliable operation — i.e. the 17 has more ability to deal with stacking of tolerances….

    Hope that helps a little……

    • Ian Argent says:

      This may be it.

      If I pull the trigger and hold it back, then pull the slide back and allow it to return to battery, if the muzzle is vertical, occasionally it does not lock up fully until I release the trigger. If I ride the slide at all during this operation, the failure to lock up is pretty much guaranteed.

      This only happens with muzzle pointed up, I cannot replicate (even by riding the slide) if the muzzle is pointed down.

      Now, doing this sparked a memory of the very first time I racked the slide on a live round with this pistol; it didn’t lock up completely and I had to give the slide a jolt to put it in battery. Never happened again, and I had assumed it was because I held on too long after “release.”

      I guess I had better start shopping for a slightly stiffer recoil spring.

      • Nick says:

        It might be as simple as getting a replacement for the stock recoil spring assembly. They do wear out…..

        On the other hand — if you want to try different spring weights, then Wolff Springs ( used to sell a steel recoil rod and a calibration pack of springs for Glocks — basically 5 springs in five different weights.

        If you change the recoil spring weight, one other thing you want to be aware of is that if you should go lighter — you need to make sure that during the trigger pull the slide doesn’t move out of battery. (Trigger bar pulls striker to the rear, compressing the striker spring — that effort can, if the tolerances stack up the right way, start to retract the slide….)

        Usually you need to make some other spring changes to the gun — but test in dryer first, before putting ammo through the gun….

        • Ian Argent says:

          I accept that they wear out, though this was a tad earlier than I would have thought. Since this is a G17L, not a standard G17, I really wasn’t considering a lighter spring. As you said, the slide is marginally heavier. (I’m not entirely sure what benefit you get from a lighter recoil spring, anyway.)
          I had been looking at the Wolff springs, since they were high on a Google search. It was unclear from their description if I went to a stiffer spring whether I needed a stiffer firing pin spring, as well.

          • Zermoid says:

            I recommend Wolff springs as well, my 1911 that I carry has them in it. Any time I replace stock springs in any gun I go for Wolff.
            Only caution is if you go to a heavier recoil spring is to test fire the gun before carrying it, too stiff a spring can cause the slide to not recoil far enough back to pick up a fresh round off of the mag, for target shooting this is no big deal, but if you are shooting to save your life…

            Change the spring and try it with the lightest load you shoot, if it cycles with that any heavier loads should work just as well.

  7. beatbox says:

    I’ll give you the response you would get in a Glock forum.

    You are doing something wrong.

    It’s a feature, not a bug.

    Hundreds of thousands of cops use Glocks every day without this problem. It must be your imagination.

    • Ian Argent says:

      Hah. There’s a reason I didn’t go to forums with this question :)

    • Zermoid says:

      If you’re on FB you may want to try this group:
      Gunsmith Corner
      I set it up and it is strictly admined to keep out the assholes, it is a closed group so you will have to join, but alot of our people are gunsmiths, and alot (like myself) are serious gun nuts and tinkerers who need a little help on occasion. Our group is for getting the dedicated gun enthusiasts and gunsmiths together to share lnowledge before they do something they will later regret to their guns. :-)