I bought my G20 Gen4 new 1 year ago now under GSSF (my 1 year warranty runs out this Friday).  Ever since having the pistol, it has had a FTF issue with ammo - since I almost exclusively shoot off the shelf ammo, I guess we could consider that the weak 10 variety...however it was a very occasional FTF.  I numbered my mags hoping that it would be one mag but no such luck, it happens to all of them.  I also have a KKM .40 conversion barrel, it happens about the same amount of time with weak 10 using that.  Thinking perhaps it needed a good cleaning, and/or perhaps the Frog Lube I was using had gotten somewhere it shouldn't, I broke the slide and the frame down to each individual component, save for the mag release spring and mag release, and ultrasonic cleaned the disassembled pieces, taking care not to let any of them touch each other, using a 3:1 distilled water to Simple Green Extreme (the aluminum aircraft safe stuff), followed by a rinse in the sink with hot water and then a good dousing with 91% isopropyl alcohol to get any water out.  I then re-lubed with Frog Lube taking care to get none around the firing pin channel area (basically from there forward I lubed, except for inside the slide rails).

At this point it sat for a while since I don't shoot much, until my bud and I went and shot end of Nov.  I had ordered 500rds of PBR Premium 165gr target load, figured my ills were solved...could not have been more wrong.  I load 10 per mag, and I was having almost every mag have one FTF.  Disgusted, I switched over to the .40 conversion and shot some Winchester 165gr target load from Walmart (100 count box), same deal, maybe not quite as bad.

At this point, I sent it back to Glock.  They sent it back to me after what they say is running 20 mags of ammo through it via 2 people, even intentionally holding it with like 3 fingers to simulate limp wristing...not one problem according to them.

So I went Monday, shot 3 boxes of 180gr Remington 10, 1 box Armscor 10.  Not one FTF.  I even held it, barely, very loose in my hands, didn't try and contain the recoil at all, sort of my own version of limp wrist test, and no FTF (that was over 30 I did like that).  Thinking that maybe Glock had fixed something and just not told me, out comes the PBR and...same problem (see pictures attached for 3 of the rounds...the last one was the worst, I took pics of it where it was marked up).  Curious I dropped the .40 conversion in there and shot maybe 60 rds of the Walmart Winchester, had one FTF.

Help...haha...I am new to this and by no means a gunsmith.  Any suggestions?

Do you have a light attached?

 Wow. The Gen 4 is the problem 10mm pistol currently.  It seems the fix every owner has corrected it swapping to a Gen 3. Is that an option for you?

Quote from: enidpd804 on March 06 2014 02:54:55 AM MST
Do you have a light attached?

Nope.  Only thing I've done to it is install Trijicon HD night sights.

Quote from: Intercooler on March 06 2014 02:58:19 AM MST
Wow. The Gen 4 is the problem 10mm pistol currently.  It seems the fix every owner has corrected it swapping to a Gen 3. Is that an option for you?

My warranty is up Friday, and Glock found no problems.  I don't know how I'd talk them into swapping for a whole new pistol.

chucky2,

I had the same issue with a Gen4 I bought about a year ago. Sent it back to Glock. They replaced a couple of parts & said it was fine. Issue got worse over a few weeks after I got it back. Sent it back to them a 2nd time. They said nothing wrong but offered me a replacement gun of my choice. I chose a Gen 3. It functions perfectly & I am really happy with it. My favorite pistol of all time.

Here is the post regarding my issues with the Gen 4 http://10mm-firearms.com/10mm-semi-auto-handguns/problems-with-failures-to-feed-with-underwood-ammo-gen-4-glock-20/

Call them & let them know it is not working & you are sending it back.

I don't know if this will make you feel better or worse, but my gen 4 20 had 2 FTF in its first 20 rounds. Over 500 rounds of reloads, Federal, and Underwood later not one more bobble. So they can work.

I just can't understand that, this many people are having issues with the Gen4 G-20's an be user error...like thumb riding the slide, bumping the slide lock or other.

What was changed in the Gen4 pistols?  The RSA was changed to make it a captive dual spring arrangement, but was anything else changed?  I Don't Know!  I was set to purchase the Gen4 G-20, as I watched some of the issues start to pop up, however a great deal on a Gen3 was presented and I moved on that purchase.  May have been a great move on my part.  Even Glock had a revision of the RSA for the gen4.  Aftermarket RSA for the newer gen4's are just starting to hit the market, they may not solve the issues.

Here is something I see with the captive spring system...they seem to fit loose, do they lack pressure at full closure of the slide to maintain positive lock up? 

Looking at the way the ammo is sitting in the FTF position seems to indicate, ejecting brass timing may be hampering the pickup feeding of the fresh cartridge.

What can cause issues related to this, are the ejected brass is being held too tightly by the extractor, not being kicked out from under the extractor, thus the fresh round encounters difficulty as it's nose pops up, being pushed to the left side or nose diving into the feed ramp.  The extractor maybe wrong one, maybe too tight of fit, totally gummed up extractor & spring, extractor could be damaged, damaged by placing a round in the chamber and letting the slide close so the extractor has to jump over the extractor rim of the cartridge.  That can damage the extractor by bending it, or even breaking it. 

The breech face of the slide if rough can slow the cartridge from riding up and under the extractor.  Damaged casings can be culprit to a tight extractor fit and sliding against the breech face as it goes into battery.

These are things to consider looking over, as you attempt to figure out you problem and diagnose the cure.

Glockmeister now has the RSA's for the Gen 4:

http://www.glockmeister.com/Glockmeister-Stainless-Steel-Recoil-Spring-Assembly-for-Gen-4-G20-and-G21/productinfo/G4SS20CS/

It comes in 17 pounds, 20, 22, and 24 pound weights. It also has some lighter weight springs for whatever reason.

I think my Gen 4 may be alright. I'll know after the next range session. Don't plan on switching to a heavier RSA yet as I heard the Gen 4 RSA handles hotter ammo better than the Gen 3 stock RSA. I like how heavier springs are finally available though.

Gen4 has problems for certain.  It might be that its not all, but its not an uncommon issue.

Heavier springs designed around the Gen3 made mine worse, and that was 22# spring.  The one pictured in 4949's post looks exactly like what I had assembled.  It wouldn't run well with Underwood 135s, which ran just fine with the stock spring.  That double spring setup does better stopping the slide than a pretty hard slam with the 22# single spring.

I really haven't spent time at the range for awhile because the weather has been terrible, or else I've been busy.  I do have a 24 pounder to try, if that doesn't do it, I may try the Springco recoil reduction setup (different kind of double tension setup) or else just use reloads that run fine (quite strong at a touch over 700 ft-lbs).

If I had to do it over, Gen3.

Greg

Thank you Everyone for your comments!

DavidF:  Will read through your thread tonight, thanks for the link!

Blueduck:  I do have some Underwood 135 and 165gr Gold Dots, I'm thinking about going to shoot them both just to see what happens with them vs. the PBR.  If anything, the Underwood should jam even more I think, since it is higher power.

The_Shadow:  I don't think I'm doing any of those things, but I am a beginning pistol shooter, so I try and not have an ego about it and realize it my very well be me.  But if I purposely hold the gun, with what is likely weak 10mm to begin with (Remington 180gr and Armscor), in a very loose manner, make no effort to control the recoil, I've got to think that should be worse for a limp wrist scenario than me having a firm grip when shooting the PBR.  Unless my having a firm grip is causing me to do something like what you're talking about.  I acknowledge that could be it, but I don't remember being aware of myself doing that (for whatever that means).

What do you mean about Glock coming out with a revised RSA for the Gen4 G20's?  I'd not heard of that...can you elaborate more on this?

You point out a loose fitting RSA.  While mine does fit decent when installing the RSA, after installing the completed slide back into the frame and racking the slide a few times, if you then field strip, the RSA has certainly moved from where it was and does seem a little loose - really what's happened is instead of being in a straight plane front to back and fully seated on the barrel, it has started moving down (in the 90 degrees direction) the barrel attachment point so instead of being seated in the bottom right by the start of the barrel, it is moved sort of like it's going to come off.  So in this respect I'd say it is a little looser...but not really knowing anything about pistols, is this expected/acceptable behavior?

4949shooter:  I may get one of those, just to try it.  Heck I'd get 2, the stock and the 20lb, just to see the difference.  Sorta pricey to just go playing...I can swing it without issue just hate throwing $$ at a problem I shouldn't even be having.

Geeman:  You're saying what he had linked is what you've already tried?  Are you having the same type of issue as me?

Chuck

Chuck, While the recall didn't include the G-20's there was a recall...http://us.glock.com/customer-service/recoil-spring-exchange  Some actually had the RSA fall out with the slide removal.  And many are having issues with the G-20 4th gens which are having the same FTF's like yours. 

This is more like what I feel is happening...

QuoteWhat can cause issues related to the picture you posted, are the ejected brass is being held too tightly by the extractor, not being kicked out from under the extractor, thus the fresh round encounters difficulty as it's nose pops up, being pushed to the left side or nose diving into the feed ramp.  The extractor maybe wrong one, maybe too tight of fit, totally gummed up extractor & spring, extractor could be damaged, damaged by placing a round in the chamber and letting the slide close so the extractor has to jump over the extractor rim of the cartridge.  That can damage the extractor by bending it, or even breaking it. 

Have you ever had an empty case remain in the ejection port?  Or get trapped bay the closing slide?  If yes!  This is why I suggest the extractor may be holding the brass too tight, then the fresh round is hitting the expended brass, the fresh round being pushed down or to the side or delaying the closing slide.

You can take the slide off, remove the barrel, then from the bottom slide an empty brass up the breech face so as the ejection rim is under the extractor.  You should be able to actually cycle an empty brass from the magazine to the chamber if things are functioning correctly.  You are looking to see it it binds up, or has problems being extracted or thrown clear of the ejection port.

I'm just trying to help you to study the problem and possibly find a solution on your own.

The_Shadow,

No no, don't take my reply as my in any way being offended, I wasn't.  I'm just saying, I completely could accept it was me causing the pistol to malfunction.  Knowing this, when I went Monday to the range, I paid particular attention to not limp wrist, keep my thumbs away from things, etc.  Now, I could very well have still screwed up...that I can also accept.  I don't think I did, but I'm not even a novice, so it could be that I did.  One thing though is, my bud who is a novice .45 pistol shooter (his first pistol), has strong wrists and forearms.  Despite being a new shooter, his groupings are very good.  When I went to the range with him end of Nov and had the issues, I had him try it...he had the exact same problems.  So I'm pretty certain limp wristing and the FTF can be ruled out with the PBR.  All the other things you pointed out though, still possibilities.

I have never had an ejection issue with brass remaining...they always get ejected.

I doubt these parts are that expensive...do you know how to replace the ejector?  From what I remember when I took everything apart to clean it in the ultrasonic, the ejector was pretty firmly embedded into the trigger assembly, so I just left it all together.  I've got a good amount of PBR left.  I could replace one, then the other, and see if it makes a difference.

I appreciate the help and advice!

Chuck

Brass gets tossed 12 to 15 feet.  I've had it land on the roof of the pistol house on stronger loadings, so I don't think thats an issue.

I do believe its a slide speed issue.  I believe the slide has too much speed. hits the end of its travel abruptly and rebounds back under spring pressure.  The stronger spring just seems to close the action faster.  I feel the round in the magazine isn't fully in place in time, which allows for differences round to round.  It is often the type of misfeed that catches the round on the top of the case rather than pushing it up from the rim.  Clearing is often pulling the slide back, round pops up, and letting the slide go chambers the misfeed. 

Limp wristing IS AN ISSUE, as when the slide reaches the end of its travel so abruptly, there is a big upward snap that must be delt with. 

I think there is a catch 22 with the springs.  A weak spring lets the slide hit its travel faster/harder.  The heavy spring seems to still not stop the slide, and when it rebounds, its under more tension and the slide returns too fast.

I think its a timing issue with heavy loadings.  The Gen4 spring is a two spring system, and the solution is going to need to be a two spring setup also.  There needs to be a stout spring that slows the slide at the back of its travel instead of allowing a mechanical rebound under spring pressure. 

Its been a long winter and I'm sure I have overthought this whole thing without trigger time to prove/disprove my theory.  Its not fact, but it is my current thinking.

Greg

I'd be willing to ship my slide to someone who has a scale and a Gen3, just to see how close to each other they are.  I'm curious...I can't believe they'd have changed the Gen4 slide to such an extent it wouldn't be very noticable, could they?