Glock 17 gen4 Endurance Test: Week 17

17-Jul-11 – 21:03 by ToddG
25,366 rounds 6 stoppages
(+1 w/non-LCI extractor)
0 malfunctions 0 parts breakages

The G17 turned in some great practice numbers this week, including tying my personal best on JodyH’s 99 Drill (95 out of 99, dropping one point on each of the four strings of fire).

The NRA Range’s target carrier system is back to allowing flat one second exposures on turning targets. This allowed me to run 100 1-second draws one evening, hitting an 8″ circle 57% of the time from my Custom Carry Concepts Shaggy underneath an untucked polo. Going that fast definitely blurs the line between aimed fire and unaimed (“point shooting”), but at least for me it was the times when I got a visual reference on my front sight that resulted in hits. Color me not surprised.

During the (unreported) Week 16 of the test, I shot a 286 on the Hackathorn Standards using my Federal 124gr +p HST carry ammo, again from the Shaggy underneath a polo. While 286 isn’t bad and just two points behind my previous personal best, it’s nothing compared to Kyle Defoor‘s recent perfect 300 on the Hack. To the best of my knowledge, Kyle is the first person who has shot a perfect score. It’s an incredible feat and a personal goal of mine. Huge kudos to Kyle.

On the subject of Federal ammunition, over the past week I had two bad rounds of American Eagle 115gr FMJ (AE9DP). One was obviously very short in overall length and the other was too long. The rounds came from the same case of 1,000. I’ve fired over fifteen thousand rounds of AE9DP through this gun in the past three months, all from the same lot as the two problem rounds. Pictured at right are the two bad rounds with a standard OAL round of the same lot number in the middle.

The Trijicon HD sights continue to work well for me. I’m still throwing the occasional shot high on the press-out, so I decided to try one of the Grip Force Adapters sent to me last year for T&E. The GFA definitely helped me get the pistol leveled out sooner in my press-out thanks to the change it makes in the grip angle. However, it increased the grip circumference just enough that it disrupted my left hand position and led to my left index finger getting in the way of my trigger finger while I shot. It was more of a mental hangup than anything else as my shooting did not seem to suffer either in terms of accuracy or speed. Still, mental hangups are no fun so I took the GFA off. After talking to a number of people who love the GFA, it’s clear this is not a common problem. Oddly enough, working with the GFA on my gun for a week seems to have cured my problem and now even without the GFA installed my press-outs are much more consistent.

Since the last report, the pistol had its 22,500 maintenance which included a detailed cleaning plus changing out the following parts:

  • recoil spring assembly
  • trigger return spring
  • magazine catch spring
  • striker spring

A few folks have asked about the magazine catch spring because it is not a commonly recommended replacement part. Based on advice from some folks who know a lot about high round count Glocks, I decided to add this to my 22.5k schedule. While the mag catch spring rarely breaks, when it does it can permanently disable the frame if the break occurs far enough down that the lower section cannot be extracted. Rather than risk one little spring bringing the endurance test to an untimely end, replacing it seems like very cheap insurance.

Obviously the major news for this update, though, is that 25,000 has come and gone. See this comprehensive review for more on that.

Train hard & stay safe! ToddG

Previous Glock 17 gen4 Endurance Test posts at

  1. 5 Responses to “Glock 17 gen4 Endurance Test: Week 17”

  2. Todd,

    I’ve been seeing an increased frequency of defective Federal AE 9mm rounds recently at the very busy “schoolhouse” where I teach deploying personnel. What we’ve seen has been underloaded (near squib) rounds and we’ve also noted some defective 124 +P HST rounds with crushed case mouths.

    By Wayne Dobbs on Jul 17, 2011

  3. Well I know that all manufactures make bad ammo from time to time but it wories me that your finding bad HST’s as that’s one of my carry loads.

    By Prdator on Jul 19, 2011

  4. Spencer,

    Just do a good Mk I, Mod 0 eyeball inspection of any carry ammo you use, no matter who loaded it. I’ve even done the chamber guage test of duty/carry ammo at times to make sure that ammo would chamber.

    By Wayne Dobbs on Jul 19, 2011

  5. Glad to hear the slide stop is holding up well- as far the Hackathorn scores well done put please clarify; I know for a fact Kyle’s score was on what Ken calls the
    ‘kiddie’ version because he told me ( still good shooting none the less) – but make no mistake there is a difference between the two

    Be safe


    By Larry Vickers on Jul 31, 2011

  6. LAV — Yes, it’s the “internet” aka “kiddie” version. For those who aren’t familiar, the differences are:

    * strings 3 & 4 (5yd SHO) are done from a retention position in the original version; depending on your point shooting ability, this can be a major difference; Ken is very insistent that these strings be shot in the original form

    * string 12 (2 on each from prone) is done as one on each, roll left or right, and one on each again in the original version; when I shot it with Ken last year, he was not particularly concerned about whether the roll was maintained especially given that exercise is now expanding past your former unit to a broader and usually less skilled audience

    * string 13 (barricade) involved two separate barricades, a high and a low, in the original version and you had to move from one to the other; when I last shot it with Ken, he stated the given the generous time limit on this string he saw no real difference between the two

    * Ken gives a 0.30 second “grace” on the PAR time while the “internet” version has evolved without that; especially on the closer range fast strings, losing the 0.30 grace period essentially takes away 10% or more of your PAR time and makes those strings substantially harder for beginner and intermediate level shooters in particular

    As I understand it, Bill Go was the person who made the modifications for incorporating the Hackathorn Standards into Blackwater’s training program.

    By ToddG on Aug 1, 2011

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