I initially posted about my Gen4 G17 that I picked up on 4-15-10 in this thread http://m4carbine.net/showthread.php?t=52911.
The below quote is my last post in this thread on my Gen4 G17.
Since that time I have put another 700 rounds through it for 2400 rounds total. NOTHING has changed on weapon and ammo since the above quoted post. Didn’t have a problem until now. However I am having some interesting results so I thought I would start my own post and track my findings here.
Yesterday 5-5-10…First day where issues started happening. Nothing that I can make note of has changed since my last shooting session. Shot 300 rounds American Eagle 124gr FMJ through my new Gen4 G17 with a light bringing up the total to 2000 rounds. Just over 1K with a light and just under 1K without a light. All 5 mags are the same and are new since this gun purchase. During these 300 rounds I Had 2 failures to lock back on an empty magazine and 1 slide locked back with a partially full magazine. Marked each magazine 1-5. Ended the shooting session as I didn’t have more time to shoot.
Today 5-6-10…Stripped, inspected, cleaned and lubed up weapon and mags. Nothing out of the ordinary noted. Mags are numbered 1-5. Shot 400 rounds of the Am Eagle 9mm ammo. Had 5 failures to lock back on an empty magazine. Magazines 1(x2), 4 & 5(x2). Had 2 slide lock backs on a partially full magazine. Mags 1 & 3.
Stripped the weapon to examine, closely inspected mags after each issue. Nothing noted out of the ordinary. Seems strange that for 1700 rounds I had zero problems and now the issues seem to be increasing rapidly. Very unsettling. I am hoping to get to the range again tomorrow and see what happens. I am fairly sure this is not a mag problem and these are the same mags that have been used for the first 1700 rounds. I will be taking other mags from my G34 that I have never had an issue with just to see what happens.
May or may not make it to the range tomorrow. Will update as soon as I can.
Not calling your shooting ability into question but is there any chance you are activating the extended slide release or keeping it from locking the slide back. I had issues with the extended release when I first started shooting Glocks so now I only run the standard slide release. Just a thought.
With an empty magazine, does the slide lock back reliably when you actuate the slide by hand? If so, I’d say the problem is with that extended slide release.
I was running an extended slide release and never had a problem, but last weekend an instructor made a minute change in my grip, and suddenly the slide was locking back with some frequency. I went back to the standard slide release and the problem went away.
That happens to me all the time. If you advocate and use a high grip, Glocks will fail to lock back on occasion. When I’m really running an aggressive grip it can happen as much as 50%.
He had a SINGLE instance of that happening, so that is nothing more than an outlier. Unless there’s something about a 3rd gen extended slide release mounted on a 4th gen frame, this is still a grip/software, issue.
The issue is proving to be repeatable in his shooting across different range sessions. Even if it’s not happening 50% of the time, I’d still consider it a lot more relevant than an “outlier.”
I agree with you that changing grip would alleviate the issue, but the extended stop exacerbates that issue (and will require even more grip adjustment).
Simply shoot the pistol in one handed drills (not a bad thing to do anyway) and see if the problem recurs; if after 500-1000 rounds there have been no additional problems, then it was clearly a shooter induced problem. If the problems persist, it is clearly NOT a thumb issue.
Surf’s level of experience is well above average, so I would assume that if his grip was causing the problem he would have noticed. With anyone else I would blame the extended slide release right away.
In some instances, simply doing one-handed may not answer it. I almost never get slide lock when shooting Glock right handed because I need all grip I can get; subsequently I cannot roll out my thumb. If interference with slide is a considerartion I’d shoot it left handed.
Possibly your mag springs are getting a bit weak and can’t keep up with the slide after the last round. Also, standard pressure ammo may not be cycling the slide all the way back giving even less time for the follower to come up and activate the slide lock on the last round.
I prefer the Wolff +10% mag springs. I have been using them since 1994 and have not had to replace one yet.
Sorry fellas, perhaps I should have clarified these points earlier and I do apologize. Just to clarify, my primary pistol right now and for the past decade has been a Sig Sauer P226, one of the most, if not the most infamous grip / issue related pistol made. Because I do have a pretty aggressive modern style combat grip, I very much use a modified thumb placement where I now quite naturally ride my primary hands thumb stacked, but slightly outward bound on my support hands thumb, just to avoid grip issues. I also teach an aggressive thumbs forward combat grip to our new guys, which invariably causes issues in their transition to Sigs, so I am very sensitive to addressing grip related malfunctions, even riding the decocker on the Sig creating light primer strikes.
I am not saying that it is impossible for me to cause this type of shooter / grip related malfunction, but it is almost non existent for my style. I do run extended slide release levers on almost all of my Glocks and have never had issues in tens of thousands of rounds, so I am very familiar with this set up. I also ran this same set up in this particular pistol for its first 1700 rounds with no issues or changes since then.
Now for the issues. While I was not doing pure isolation shooting to try and troubleshoot the problem, I was however cognizant of the problem and immediately when I had a failure, I paused, holding my exact grip and closely examined my grip and the weapon to see if there was anything immediately visible. Nothing that I could determine just from visually looking at my grip or the pistol itself.
I also pulled the guts and everything looks good to go and installed correct. It is really puzzling that the weapon was having failure to lock back issues and locking back with partially full mags. I would more commonly expect one or the other. In any event, as Doc mentions I intend to do some pure isolation shooting and rotating proven mags and running these new mags with my absolutely trouble free G34 with an almost identical set up. I am pretty convinced that it isn’t a mag issue, but can’t completely rule it out as of yet.
I do appreciate all of the brainstorming! Sucks but I don’t have time to make it to the range today and I don’t shoot on weekends, so this will have to wait til next week. I was about to pick up a Gen4 G22 and was eagerly awaiting other upcoming model releases, so I am real anxious to get this worked out.
OK, to update this one. Since I pulled the guts and took a look inside, everything looked to be good to go. I simply put it back together, cleaned the weapon and lubed it up as normal.
I do not know why as I haven’t changed anything else but I have not had a single issue and I am currently up to 3400 rounds through it. Logic seems to dictate that by gutting it and putting it back together cured something, but everything looked correct and I didn’t change anything.
I would also find it strange that I had a grip brain fart for 300 or so rounds, but anything really is possible. If it were grip related, I do find it more odd that I haven’t produced another grip brain fart in the last several hundred rounds since I gutted it.
Not sure what to think at this point. I will see what happens in the next 1K or so rounds through it.
Stranger things have happened and maybe something was corrected in your detailed strip and assembly. I say keep shooting it and keep us posted. It looks like it is going to be a high round count gun for you and many of us are interested in knowing how the Gen4’s will handle it. Thanks for sharing your experience.
