Glock 17 80% FTF

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  • lazarus

    Ultimate Member
    Jun 23, 2015
    13,678
    Okay, so I’ve done everything I can think of and possibly research on my Glock 17 80%. It is a V1.5.

    It will fail to fully got in to battery about 1 in 30 rounds generally. A light tap on the rear of the slide and it pops in.

    Originally it was that the firing pin striker liner was not installed corrrectly and the slide stop was in backwards. Replacing those took it from every rounds loaded automatically was a FTF to about 1 in 10.

    I’ve honed the edge of the barrel hood and slide interface and that improved things ever so slightly. As well as disassembled and bent the striker reset arm (or whatever it is called) out slightly as it wasn’t shaped quite right and was putting some pressure on the side wall of the lower.

    The rails appear machines correctly and by hand it goes in to battery 100% of the time, even if I lower the slide till it is just barely touching a cartridge (using dummies) and release it. It won’t go in to battery if I lower it further till the round is starting to chamber and I release it. The recoil spring at that point doesn’t appear to have enough force to overcome the extractor lipping over the cartridge case.

    I have NOT replaced the recoil spring assembly. It is a Glock factory part and factory weight for a 3rd gen.

    So suggestion of next attempts? Should I bite the bullet and get a Wolff guide rod and a couple of recoil springs that are maybe 1 and 2 pounds heavier weight and try that?

    PS I am absolutely positive I am not limp wristing it or riding the slide stop or slide.

    PPS is this occurs with the same apparent frequency for UMC and white box, steel case, PPU and Winchester NATO and a few other loadings. Only one I haven’t seen it happen on is are Remington Golden sabers, but I just may not have shot enough of them (only one box of 124gr +p) as occasionally I can get through an entire box without this occurring.

    Part of my thought at this point is that since it is occurring with all weights and power of cartridge, that the recoils spring doesn’t have quite enough force to always snap it back in to battery against whatever frictional forces are fighting it. I am also wondering since it never seems to occur until about 15-20 rounds in...ever now, if it is parts heating up and expanding a bit that is what is causing the slight extra drag. After my last range session I did hone the barrel hood and slide just a tiny bit more with a keeper file and some 220, 400 and 1000grit sand paper. Not a ton, just a little more.
     

    SWO Daddy

    Ultimate Member
    Jun 18, 2011
    2,468
    Does the channel for the recoil spring have sufficient clearance? What about the flat spring holding the takedown in place, is it flush with the channel for the recoil spring? Both of these issues can cause the malfunction you describe.
     

    jonb219

    Active Member
    Oct 17, 2013
    132
    Falling Waters, WV
    I'd start with the suggestions above.
    I had this same problem with a factory Glock. In my case, replacing the extractor/depressor/plunger was the solution. This may be a good place to look next.
     

    Bountied

    Ultimate Member
    Apr 6, 2012
    6,894
    Pasadena
    Try a heavier recoil spring? 17lb is stock I think try 19lb round coil style. They sell them on amazon. Also try racking the slide about 50 times, get it worked in. My second build had a similar issue with the flat spring getting stuck on a non smooth part in the channel. I used a dremel to polish it and it fist the issue.
     

    StantonCree

    Watch your beer
    Jan 23, 2011
    23,932
    Is the slide lock lever installed correctly? This seems to be the most common issue causing your complaint.

    I’ve had that issue with 2 of the 3 I’ve done cuz I’m an idiot lol.
     

    lazarus

    Ultimate Member
    Jun 23, 2015
    13,678
    Is the slide lock lever installed correctly? This seems to be the most common issue causing your complaint.

    I’ve had that issue with 2 of the 3 I’ve done cuz I’m an idiot lol.

    Yup. That was my first issue.

    The recoil spring channel has plenty of clearance. The take down spring is flush with the channel IIRC. I'll double check that. If it is below the channel, is that an issue? Just above the level of the channel is an issue, right?

    I could try the extractor/depresser/plunger. That is one thing I didn't try. Though it appears to be working just fine. Well, as near as I can tell. No clue how to check if there is extra friction or something in it, but it is locking and unlocking the firing pin correctly and the extractor doesn't seem to have too much force (I don't think) and it easily holds a loaded cartridge in place with the slide removed. I can slide one under the extractor and shake the slide all around and the cartridge stays in place.

    I did have to replace the ejector with a gen 4 ejector as I was getting brass to the face from the gen 3. It ejects about 2-4 feet to the side. Only handgun I have that tumbles the brass out a shorter distance is my Colt Official Police :lol2:

    All my commie guns will put an eye out at 30 paces. My one Fascist/Former Fascist (P1) tumbles them out about the same distance to the left (still so weird to me that it ejects that way).
     

    lazarus

    Ultimate Member
    Jun 23, 2015
    13,678
    The flat spring for the slide stop is recessed. Not sure how clear it is in the picture. I don’t think the recoil spring is rubbing anything, but the metal of the block/slide is raise maybe .01-.02” above the plastic channel and if I take the recoil spring/guide rod off the slide and lay it in the channel, the spring does rub along there a little. Not sure how natural that really is compared to being mounted in the slide. I could smooth that area out some with my dremel.

    Thoughts on either of those?

    I need to order a couple of other things from Wolff, but no rush on them. So a new guide rod and XP spring(s) at the same time isn’t a bad idea. I have to get to the range early next week. For sighting in my ML and I don’t want to spend much time doing other stuff, but taking my Glock and running a box through it isn’t a huge ask.
     

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    sinensis

    Member
    Sep 4, 2018
    67
    Columbia, MD
    If you're close to me, I can swap my G17 glock parts into yours to test. But I think you have way too much oil in there, you don't need to oil the channel if I recall. I've never oiled mine, in fact, it looks like a lot of oil all over on that picture?
     

    jhcrab

    Active Member
    Jun 28, 2012
    499
    Howard Co.
    If you're close to me, I can swap my G17 glock parts into yours to test. But I think you have way too much oil in there, you don't need to oil the channel if I recall. I've never oiled mine, in fact, it looks like a lot of oil all over on that picture?

    The excess oil was my first thought when seeing the picture.
     

    lazarus

    Ultimate Member
    Jun 23, 2015
    13,678
    It is pretty wet. Someone suggested awhile back oiling the recoil spring. I certainly need wipe it out. I could be wrong, but I wouldn’t think that would cause FTF issues.
     

    StantonCree

    Watch your beer
    Jan 23, 2011
    23,932
    I also see all the ammo you used is shit ammo. Get a nice hot +P and run a box through.

    My 3rd gun had the same issue but everything was installed correctly. After two mags of hot Winchester +p it runs great.
    If your near colesville in MoCo I’ll give you some stuff i think my accelerate the break in. If this stuff wo f cycle then it’s the build somehow
     

    sinensis

    Member
    Sep 4, 2018
    67
    Columbia, MD
    Add a little bit of oil to a rag and wipe the recoil spring would be all I would do. Your channel looks fine to me, do you get any hesitation if you pull the slide back and walk it forward? Can i see the bottom of the completed upper slide and the rear rails of the P80?
     

    lazarus

    Ultimate Member
    Jun 23, 2015
    13,678
    I took a dremel to the recoil spring channel. Just to clean it up a little. I also noticed that the locking block screws were sticking in past the locking block. I see no evidence the spring is rubbing on them. So those got ground back a couple of hundredths of an inch. And the floor/mouth got ground back a hundredth or two also to clean it up.

    Other than the original milling with my drill press/hand drill, I didn’t have a dremel at the time. So all cleanup has been with jewler’s files and sand paper.

    Here is a new picture of the locking block/recoil spring channel, rear rails and bottom of the slide.

    PS I’ve run a few boxes of 124gr NATO PPU and Winchester through it as well as a box of 124gr +p golden sabers. No FTF on the one box of golden sabers, but of the 4 boxes of Winchester/PPU NATO ammo, at least 4 or 5 FTF between them. This build has maybe 700-900 rounds through it at this point. Mostly basic 115gr.
     

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    lazarus

    Ultimate Member
    Jun 23, 2015
    13,678
    I don’t notice any hesitation or sticking spots racking the slide either in the rearward or forward motions. Not owning another one to try, I can’t compare against a known good one. The unlocking action rearward and locking in returning to battery has a bit of hesitation/different pull weight to it, but it doesn’t seem abnormal to me from what I remember of other Glocks I’ve tried or against the couple of other browning action handguns I have.

    Maybe it is a hair smoother now that I dremeled the channel some more? That could also be in my head.
     

    sinensis

    Member
    Sep 4, 2018
    67
    Columbia, MD
    I'm not seeing any brass/copper rubbing on the bottom of your slide, did you clean it off really well? I was expecting something like this (picture off internet):

    slide_barrel.jpg


    mine look worse than that, but I likely didn't clean it as well or mine rubs way too much (500 rounds through it).
     

    lazarus

    Ultimate Member
    Jun 23, 2015
    13,678
    It just isn’t coming across in the lighting. The same piece along the round feed on the slide has a nice bronze color to it like the picture you posted does.
     

    Magnumite

    Ultimate Member
    Dec 17, 2007
    6,564
    Harford County, Maryland
    Where is the failure to feed occurring? A pic of the malfunction would help.

    Also your pistol should run on your blasting grade ammo. I didn’t notice anything substandard you are using.

    Additionally, the biggest difference in the GS’s and the ball ammo is cartridge overall length. That would be a clue to the cause of the feeding issues.
     
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    lazarus

    Ultimate Member
    Jun 23, 2015
    13,678
    It is running almost all the way forward in to battery, but then stops. I have to tap the slide to get it fully in to battery when that happens. It usually requires a very light tap. Some of the time it is out of battery just enough that the firing pin will fall and a light primer strike occurs. Other times it is just barely out of battery enough that the safety will prevent the striker from firing.

    Basically it loads the cartridge to the point where the barrel is beginning to tip back in to battery and no gap is visible between barrel hood and slide (if that makes sense, ID the cartridge is not visible), but usually there is slight visible misalignment/hasn’t tilted back in to battery fully.

    What is puzzling me is I can sit there, load a bunch of dummy cartridges in to a magazine and slowly lower the slide till it barely touches a cartridge and release it, and it loads a cartridge 100% reliably. I’ve sat there and run 50 or 60 dummies through this way. I did have to hone the barrel hood/slide interface a little to get it there. It would sometimes FTF when I was doing that test before I took some 220 and then 400 grit and finally 1000 grit sand paper to it.

    It is anything from about 2 to 4 rounds out of 50 where this is happening. I don’t think it has happened on the first few rounds out of a mag or the last couple, but when you are taking an average of about 1 FTF per 17 round mag...

    Only thing it hasn’t happened with are Remington Golden Sabres, but the single box I ran through it I don’t think is sufficient to say it won’t happen with them. It has happened with UMC 115gr, independence 115gr JHP, Wolf steel 115gr, PPU 124gr NATO, Winchester 124gr NATO and 115 and 147gr white box. I can’t remember if it happened with IMI JHP, but I only ran part of a box through it (my P1 ate half the box to see if it would run in it. Nope. Still no to IHP ammo in my P1. Flawless with ball).

    Anyway, after this last time, I did a very fast sanding pass on that same barrel hood/slide interface and cleaned up the recoil rod/spring channel with my dremel per the pictures/mention. Not sure if that did anything. I can’t tell if it is smoother. It feels smooth racking the slide.
     

    erwos

    The Hebrew Hammer
    MDS Supporter
    Mar 25, 2009
    13,866
    Rockville, MD
    It is running almost all the way forward in to battery, but then stops. I have to tap the slide to get it fully in to battery when that happens. It usually requires a very light tap. Some of the time it is out of battery just enough that the firing pin will fall and a light primer strike occurs. Other times it is just barely out of battery enough that the safety will prevent the striker from firing.
    This sounds a lot like your striker spring is overcoming the recoil spring. If you want to test this theory out, hold back the trigger hard while you slowly let the slide try to reset, especially not from full distance.
     

    lazarus

    Ultimate Member
    Jun 23, 2015
    13,678
    This sounds a lot like your striker spring is overcoming the recoil spring. If you want to test this theory out, hold back the trigger hard while you slowly let the slide try to reset, especially not from full distance.

    Oh, good idea. Thanks, I’ll test when I can.

    I think it is stock striker spring weight. Any thoughts on what to do if that is the case? Go a step lighter on the striker spring? Or a couple of pounds heavier on the recoil spring?

    Or it should be. If it matters the trigger has a reduced weight spring IIRC.
     

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