Glock 17 gen4 Endurance Test: Week 29

6-Oct-11 – 15:25 by ToddG

39,572 rounds 8 stoppages
(+1 w/non-LCI extractor)
0 malfunctions 0 parts breakages

Update on the magazine problem: During my first range session after discovering the initial problem with three new magazines, one of my previously dependable magazines (the one I’d been carrying on my belt as a spare since the beginning of the test, in fact) began dropping during recoil. Just a few days before, that magazine had been fine. Needless to say, it was a disturbing discovery. No longer able to trust the gun but still fairly certain the problem was directly related to my grip against the mag catch, I reversed the mag button so as to actuate it with my trigger finger. I’ve been using my trigger finger on the mag release since the late 90’s with my Berettas, SIGs, M&Ps, and HKs. It took just a short while to reacquaint myself to make it work with the Glock again.

This weekend, I’m hoping to have at least one student in class using a G17 or G34 who’ll volunteer to run my “suspicious” magazines to get some more data on their condition. As I mentioned last week, until I get a clearer idea of whether the magazines are bad in general or just bad in my gun with my grip, I’m not prepared to decide whether they should be counted as “broken” in terms of the endurance test.

Update on the recoil spring: The new 0-2-4 recoil spring assembly was installed in the gun without fanfare. The gun was working with the previous spring; it’s working with the new spring. The important news, of course, is that there is now one universal spring for all gen4 G17 pistols regardless of whether they have a counterbored nose ring. That means my G17s (both of which lack the counterbore) will have a long supply of RSAs into the future.

Shooting: Obviously, most of my week was spent practicing reloads to rebuild “muscle memory” using my trigger finger instead of my thumb to drop the magazine. Interestingly, I found that my reloads are about a tenth of a second faster using my trigger finger. However, the angle I place the gun during the reload is a bit different, so I am fumbling the mag insertion once in a while. The fumbles tend to cost me a quarter to half a second. So the cumulative gain has only been 0.03 seconds (which is essentially meaningless). Still, with practice I expect that I’ll be able to be more correct and consistent with gun placement and the fumbles should go away.

The  other change is that my splits have dropped by a pretty consistent 0.02 seconds. Again, nothing to write home about but it underscores the problem I was having with the mag drops. I’m now getting a firmer grip with my support hand, putting more contact patch against the gun’s left panel. It’s translating into noticeably less movement. The mag button was getting in the way of my hand before.

I shot the 99 Drill again this week, scoring a much improved 91 (-2, -2, -1, -3). Clearly, I fell apart on the 15yd stage. That’s no surprise considering how poorly I did shooting the Drill of the Week:

A 91-1X. Heck, I think last week’s fifty yard group was tighter than that. The difference is that for the 50yd group last week I could take a 6 o’clock hold; I was only measuring group size, not targeting. Hitting the bull at 25yd meant I had to shoot not just a tight group but a centered group. The Trijicon HD sights cover so much of the bullseye that it was hard to get consistent elevation. Still, I should have been more patient. I should be able to keep everything in the black, HD sights or not.

But at least I drifted my sights, did you notice?

I also shot the 4567 Drill, scoring a 13.12 (2.70/4.18/3.67/2.57) clean. It’s a neat little test. The accuracy standard is tight enough that most folks won’t be able to blaze away blindly, and it throws in the SHO and WHO segments which don’t exactly play to most folks’ strong suit.

This coming week I’m in Salt Lake City teaching Aim Fast Hit Fast. I’ve received two of the latest generation 9mm Glock ejectors for the gen4 pistols and will probably install them before class begins. The class will provide a good opportunity to test the ejector before I rely on it off the range. Check back next week for the results.

Train hard & stay safe! ToddG

Previous Glock 17 gen4 Endurance Test posts at

  1. 16 Responses to “Glock 17 gen4 Endurance Test: Week 29”

  2. Are you sure it’s not the mag catch? It’s just a dinky piece of plastic that may have been damaged somehow…

    By Andy S on Oct 6, 2011

  3. It’s fumbles…it was always fumbles….

    But seriously, as soon as that becomes second nature, we can expect a new all time low/amazingly awesome fast score right?

    By JConn on Oct 6, 2011

  4. Todd;

    What do you think changed about your grip/mag release interaction that started causing problems 35,000 plus rounds into the test?

    By rsa-otc on Oct 6, 2011

  5. Complete tangent…The clinch pick matched up with the Mac and G17 = major drool factor. Nice.

    By John on Oct 6, 2011

  6. Going off of rsa-otc, I’d find it really interesting if your grip changed after all these rounds……well, after all these years. Did you ever have this problem before? Have you tried to just shoot a lot of rounds through it SHO?

    By Tyler on Oct 6, 2011

  7. Todd,

    Are you saying that you drifted your rear sight to correct a windage issue?

    By Nick Drakulich on Oct 6, 2011

  8. Hey Todd, thanks for the photo which I’m guessing is honoring Steve Jobs. A true visionary.

    Keep training.

    By Arik on Oct 6, 2011

  9. Nice tribute to steve jobs. Very classy.

    By 167 on Oct 6, 2011

  10. Andy S — Anything is possible, but the catch appears fine and it’s difficult to imagine it suddenly going bad simultaneous to the introduction of the new mags.

    rsa-otc — I doubt it was a change to the grip. I think something about the system, overall, no longer tolerated my grip.

    Tyler — I’ve purposely made changes to my grip plenty of times to accommodate a new gun, etc. But nothing has changed concurrent to the mag drops except the mags themselves.

    Nick — Yes, I’ve gone more than six months knowing my gun was shooting just a hair left at 25yd. The 50yd shots last week reminded me of the need to change, and this week’s DotW motivated me to do it right away.

    Thanks for the compliments on the photo, gentlemen. As I said on the forum, it must be comforting to know that as you take your last breath, you’ve had an incredible impact on the world. While he is thought of for so many other things, without Steve Jobs (and Woz) the entire idea of having your own computer at home may never have taken off…

    By ToddG on Oct 6, 2011

  11. Looking forward to shooting the endurance Glock this weekend, Todd.

    By MichaelD on Oct 6, 2011

  12. Same here. Mine was hitting about 1.5″ left @ 7yds with the rear sight centered.

    By Nick Drakulich on Oct 6, 2011

  13. How can I get one of thise clinch picks? I have been trying to get one for almost 2yrs. I can’t find them anywhere.

    By Jeff Arms on Oct 7, 2011

  14. Todd,

    When I download the 4567 target it comes out as a small circle. I try to enlarge it to no avail. All the other PDF targets on your sites work as advertised. Can you offer a remedy?



    By MikeM on Oct 7, 2011

  15. I’m out of town until Tuesday. I’ll look into it then. Sorry.

    By ToddG on Oct 7, 2011

  16. MiikeM — The 4567 target linked has been fixed.

    By Tom Jones on Oct 7, 2011

  17. Possibly losing mag-catch spring tension? I’ve seen a similar problem develop on another platform.

    It turned out that the shooter had been bumping the magazine release the whole time, but only after a few months of shooting did the mag-catch loosen up enough that it cause actual problems.

    By ZK on Oct 7, 2011

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