Gen4 Glock 17 Endurance Test: Month 15

1-Jun-12 – 00:00 by ToddG

68,266 rounds 18 stoppages
(+1 w/non-LCI extractor)
0 malfunctions 3 parts breakages

The G17 didn’t get much range time this month and in fact hasn’t been shot since the Eleventh. But during that first week and a half of May, quite a bit happened.

First, the pistol suffered two more premature lockbacks during normal firing. Sure enough, once again it was a broken spring on the factory Glock extended slide stop. This time, it broke with less than 4,000 rounds through it. Because these breakages result in an interruption of the gun’s cycle of operation, I did not feel comfortable trying yet another. Instead, as I mentioned earlier this month in the Priorities post, I switched back to using the Vickers Tactical slide stop. While the combination of my short thumbs and the long reach required by the added Crimson Trace LG-850 Lasergrip make the Vickers lever a bit harder to reach, its proven durability (my first one went 45,000 rounds before breaking) is far more important.

Next, the G17 and I were off to Rogers Shooting School for a week. I did in fact clean the test gun just before going to Rogers. Exactly 15,125 rounds went down the barrel since the last time it was cleaned in early December 2011. While obviously not advisable by any means, it’s certainly a testament to the Glock’s design that the pistol is capable of working with so little day to day care.

My fourth trip to Rogers, this was a very successful week for me and the G17.

  • I shot an Advanced score each of the six times we took the 125-point “Test” that has helped make the Rogers school so famous. For comparison, in 2008 when I attended with the M&P9 I only scored Advanced four times.
  • My best score for the week was a 123 (cf, 117 with the M&P9).
  • My aggregate for all six tests was a 711 (cf, 665 with the M&P9).
  • The G17 helped take home my second Red Pin, given for being top shooter in class.

I have to admit, the gun did a great job. While I’m not crazy about the way the trigger feels, I cannot say it hurt my shooting or cost me any points. Previous issues I’d suffered shooting weak hand only with the LG-850 Lasergrip disappeared and in fact I did particularly well on the WHO stages at Rogers, dropping only 11 total WHO points out of 192 possible during the week. And as for the Vickers slide stop, I don’t recall having a single issue reaching it all week whether two handed, SHO, or even WHO. Altogether it’s an excellent example of a gun that might not feel the way I want, but it works excellently. That’s been a constant theme of the Glock test from the beginning.

However, even without the announcement of the next test pistol, the Glock test might well be coming to an end soon anyway. During my post-Rogers inspection of the gun I discovered the minor erosion on the breechface you can see in the photographs (left and at the beginning of this entry). I’ve spoken with someone at Glock and for now I’m going to keep an eye on it. If it continues to worsen, I’ll send it in to Glock for evaluation. If Glock feels the slide needs to be replaced, that will be the end of the test.

Train hard & stay safe! ToddG

Previous Glock 17 gen4 Endurance Test posts at

  1. 19 Responses to “Gen4 Glock 17 Endurance Test: Month 15”

  2. Are you going to do some accuracy testing before it ends?

    By Shenaniguns on Jun 1, 2012

  3. Shenani — I did a test at the 50,000 round mark and will do another before the test ends regardless of whether that is due to starting the next test or sending the gun back to Glock.

    By ToddG on Jun 1, 2012

  4. Of late, breechface erosion has become an issue with many Glocks–especially those in .40 and when using lead free ammo…

    By DocGKR on Jun 1, 2012

  5. I have one G34 runs flawlessly for past 7 years. Otherwise, 2 cracked breechfaces, 1 cracked slide, and 2 with left rear rail breaking (3 guns). I can’t get to 50K without replacing a frame or slide.

    By Glockshooter on Jun 1, 2012

  6. DocGKR, what do you think that is due to? Perhaps it is due to Glock no longer using tenifer and substituting it for the other finish?

    By Cool Breeze on Jun 1, 2012

  7. “Tennifer” is a marketing name for a nitro-carburizing process (forgive the possible spelling error) that hardens the surface layer of the steel. They’re still using a nitro-carburizing process on the pistol’s steel parts, but it’s possible they may have changed the way they go about it. From what I understand, the exact method used for nitro-carburizing and the recipe used with whatever method is selected can have an impact on the service you get from the end result.

    Todd can speak about that a little more intelligently.

    By TCinVA on Jun 1, 2012

  8. Could it be that Glock only surface-hardens the slides instead of through-hardening? Once the battering and erosion goes through the hardened outer layer, the softer inner layer would be easy to break/split/crack.

    Could it be, also, that Glock doesn’t fit barrel to frame so the barrel hood bottoms out on the slide before complete lockup, which also slams the cartridge in to the breech face. Thereby causing faster wear and breakage?

    By GhettoSmack on Jun 1, 2012

  9. It is my understanding from the armorer’s course that with the Gen4 Glocks the slides are produced in the United States so some changes did have to be made to the hardening process because the EPA wouldn’t sign off on the old method. At least that is what the instructor said, take it for what it is worth. They probably aren’t always the best source for information.

    By 167 on Jun 1, 2012

  10. GhettoSmack: If the whole slide were as hard as the nitrocarburized surface it would shatter in no time.

    By Marc on Jun 1, 2012

  11. @Todd, what type of ammo was used? Do you inspect spent cases? Perhaps you were getting propellant gas erosion caused by undersized primers in a certain run of ammo.

    By cct125us on Jun 1, 2012

  12. I’ve not noticed any signs of gas escape from primers. The damage became apparent after my trip to Rogers, of which almost all the ammo was from the same lot of 115gr Blazer TMJ I’ve been shooting all along. A few hundred rounds were from the same lot of 124gr Blazer TMJ Cleanfire that most of the other students were shooting all week long without incident.

    By ToddG on Jun 1, 2012

  13. Quote: “I shot an Advanced score each of the six times we took the 125-point “Test” that has helped make the Rogers school so famous. For comparison, in 2008 when I attended with the M&P9 I only scored Advanced four times.
    My best score for the week was a 123 (cf, 117 with the M&P9).
    My aggregate for all six tests was a 711 (cf, 665 with the M&P9).”

    I can’t dispute that you might shoot the Glock better than the M&P, or even that the Glock might be more accurate.

    But couldn’t it also have been a case that you improved as a shooter since you were last at Rogers in 2008? How many rounds have you fired since then? 100,000? More? Haven’t you continued to train under other instructors and learn from your shooting partners, and learn from the classes that you teach yourself? Did you do a better job gaming the Rogers test this time around?

    I have nothing against the Glock, but just can’t help but think I’d be a lot better if I had shot, trained and studied as much as you have since 2008. I know you were working hard; don’t give the pistol all the credit!!!

    By bobsineaa on Jun 1, 2012

  14. Todd: I figure that there is a good chance that Glock will say “don’t use the slide anymore” no matter what because lawyers don’t like to take chances (you know that from your law school days). From what I can see in the photos, though (and of course they aren’t 3D s it’s hard to say for sure)it doesn’t look like you have a problem yet.

    By SteveJ on Jun 1, 2012

  15. I had the same thought as bobsineaa. You don’t know how you would have done on the test if you had taken it with your M&P9 or your P30. It would be shocking and disheartening if you didn’t score better than you did 4 years ago. So it’s at least possible that the G19 did hinder your score. Go take it again ASAP and use a different gun and report back :-)

    You didn’t use the laser during the test I assume?

    By XKL on Jun 2, 2012

  16. In 2003 — five years before the Rogers/M&P trip — I shot all six Advanced scores with a SIG P220ST (.45 single stack). The M&P and I didn’t fare well at Rogers, simple as that. That’s not a slam on the gun, and you’re absolutely right that if I’d been shooting the M&P over the past four years instead of jumping to and from other guns I might have shot just as well with an M&P last month. Or not. We’ll never know. I can only compare the data I have, not the data I wish I had.

    By ToddG on Jun 2, 2012

  17. I understand about simply shooting the Glock better.

    However, I’m not much concerned with whether you personally shoot the Glock better than the M&P (or whether anyone does.)

    Rather, your post makes me curious how you’ve improved since 2008. Given that I’m envious of your range time and ammo expenditure over the years, it would be disheartening if you didn’t shoot the Glock better than the M&P. I got the impression you seem to be attributing the improvement since 2008 to the Glock.

    While I’m sure you are at the level that returns started diminishing long ago, I wonder what improvements you made in those 3 years of shooting. Do you have any data for that? Maybe comparing times on drills using the same gun over the years?

    (Your improvement or lack of probably has no real relevance to me, as I’m not at your level I have still have plenty of low hanging fruit to pick. But it still might be interesting.)

    Thanks. I enjoy this blog.

    By bobsineaa on Jun 4, 2012

  18. I jumbled my syntax on second to last paragraph.

    What I meant was “your improvement, or lack thereof, whichever the case may be when comparing apples to apples.”

    By bobsineaa on Jun 4, 2012

  19. bobsineaa — I don’t have multi-year data with one gun. I agree that would be interesting and informative if I was shooting that gun seriously on a regular basis. But for me to pick up, say, a Beretta 92G and run it cold right now as a comparison to the Glock would be unfair. I’m dialed in with the Glock but haven’t trained with a Beretta in years.

    Like you, I also want to believe that my base shooting skill is improving over the years irrespective of which pistol I’m using in a given month.

    I always felt that I shot the M&P well and to this day I still like the ergos on the gun. With APEX parts, it’s easy to get the trigger tuned to my liking. None of that changes the fact that when I took an M&P to Rogers, I was frustrated with my performance compared to how I’d done years earlier with a .45 caliber single stack double action pistol.

    FWIW, many of the instructors at Rogers use and prefer the M&P.

    By ToddG on Jun 4, 2012

  20. this is what a true range test means , after seeing these kind of test on a glock g 17 gen 4 I am going for one to use in ipsc production


    By fellas on Jun 10, 2012

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