Gen 4 FTF (nose up)

[Species]

Just thinking out loud here........if they are needing that much ammo to replicate the issues; it makes me wonder whatever the issue is, is it sporadic enough to only know there is an issue; but what is the problem.....i.e. the frame is not capable of handling the higher end ammo, RSA issue, mag/follower issue, slide, feeding ramp or a combination of all the above. 

It would be nice to see the results of their testing.

Also thinking out loud: in my informal malfunction analysis I have pretty much ruled out the feedramp/barrel and recoil spring assembly.  I have a KKM barrel and used aftermarket spring assemblies.  I could get the malfunction to reproduce itself 100% of the time with the KKM barrel and/or the aftermarket springs and guide rods.  I used two different types of guide rods and two different types of springs over the last couple months.

I also don't think it is the followers or springs in the magazines.  I used +10% wolff magazine springs and both #3 and #4 followers and the malfunction was 100% with those various parts.  I am still curious if anyone has had issues with Gen 4 mags in a Gen 3 gun.  Glock now only makes Gen 4 mags so I hope that they are not the issue.  All new Gen 3 guns ship with Gen 4 mags.   

The majority of the parts on the Gen 4 are identical to the Gen 3 so you can pretty much eliminate the internal parts and pieces of the trigger assembly, slide lock, etc.  Could be the ambi mag release button, but I find it hard to see how that could cause the malfunction.  Unless the ambi catch that is cut into the bodies of the magazine has something to do with the way the follower travels up and down inside the body.  I thought about that, but I don't have any Gen 3 mags to compare to my Gen 4 mags.  The armorer I spoke to didn't think it was a magazine issue because most of the complaints they get state that the malfunction happens in all the magazines customers have..... 

In my mind I am thinking it is the locking block or the frame.  The locking block is part of what forces the barrel to the correct feed angle during the action cycling.  if the locking is machined incorrectly or sits in the frame at the wrong geometry I think it could cause improper feed angle.  I don't know if the locking block is the same on Gen 3 as Gen 4.....again just me thinking out loud.  The frame is definitely different on the Gen 4 and, beside the recoil spring, is the biggest change made to the platform.  visually I could not see anything that appear to be a problem.   Like I said above, perhaps the well the locking block sits in is not correctly formed and caused problematic geometries.  Before I sent my Gen 4 back in I did a non-scientific flex test of the frame using my "brute force meter" and the frame felt pretty robust in all the right places.  But I think a very minor amount of flex in the wrong places could cause the issue.  Potentially a minor flex in the frame combined with another unknown factor could create the issues as well. 

Those are my random thoughts out loud.  Definitely not based on any facts, just the many late nights I have stayed up thinking about my problem G20.  Like you mentioned, I too would like to see the results of their testing, but obviously we will never know what they find.  Maybe a couple years down the road one of us will be on the phone with an Armorer who we catch in a talkative mood and he will spill the beans   

[chucky2]

They can't need that much ammo to actually replicate the issue.  Out of lets say 50 rounds, mine will FTF at least once, if not 2-4x.  They shouldn't need a ton of ammo to get high speed captures of what is happening.  Now, to make changes and do testing or whatnot, yeah, I can buy it takes thousands of rounds.

[Species]

Just to update everyone on this situation.  I finally got my new G20 Gen 3 a couple weeks ago from Glock.  They shipped it to my FFL with a few extra magazines which was a bonus.  It took Glock about 2 weeks to get the replacement out the door.  Not too bad all things considered.   Overall I have to say I am pleased with Glock and how they took care of me.  Not so pleased with the performance of my Gen 4, but Glock stood behind their product and made things right by sending me a Gen 3.  Will I buy another Glock.....probably not.  Am I happy with Glock and their customer service....yes I am.

The Glock armorer who was handling my case called me when they were shipping the pistol out to tell me he personally fired 100-150 rounds of the hottest stuff he could find and the replacement ran perfectly.  I appreciated that phone call.  He said 25 of the rounds he fired were Underwood 165 grains - that was all they had on hand.  The pistol was pretty dirty when I took it out of the box.  Not bad dirty, just looked like it had been to a good range session.  That made me feel better that Glock took the time to test it out with what little hot ammo they had on hand before sending it out the door.  There was not a scratch on the gun, just dirty.

I have not been out to shoot it with any hot loads yet.  I have only had the chance to shoot some Armscor range ammo and it worked great.  I burned through all my good stuff testing the Gen 4 with various springs, mags, followers, loads, COAL's, etc and haven't had the chance to load up anything exciting.  I hope to find some time this weekend to load up a few hundred rounds and get out and test it and see how she runs.  I feel a lot more comfortable with the Gen 3 and don't doubt it will perform flawlessly.

[chucky2]

Congrats Species!  Question:  Does your Gen3 have the extended mag release that the Gen4's have?

[redbaron007]

Just to update everyone on this situation.  I finally got my new G20 Gen 3 a couple weeks ago from Glock.  They shipped it to my FFL with a few extra magazines which was a bonus.  It took Glock about 2 weeks to get the replacement out the door.  Not too bad all things considered.   Overall I have to say I am pleased with Glock and how they took care of me.  Not so pleased with the performance of my Gen 4, but Glock stood behind their product and made things right by sending me a Gen 3.  Will I buy another Glock.....probably not.  Am I happy with Glock and their customer service....yes I am.

The Glock armorer who was handling my case called me when they were shipping the pistol out to tell me he personally fired 100-150 rounds of the hottest stuff he could find and the replacement ran perfectly.  I appreciated that phone call.  He said 25 of the rounds he fired were Underwood 165 grains - that was all they had on hand.  The pistol was pretty dirty when I took it out of the box.  Not bad dirty, just looked like it had been to a good range session.  That made me feel better that Glock took the time to test it out with what little hot ammo they had on hand before sending it out the door.  There was not a scratch on the gun, just dirty.

I have not been out to shoot it with any hot loads yet.  I have only had the chance to shoot some Armscor range ammo and it worked great.  I burned through all my good stuff testing the Gen 4 with various springs, mags, followers, loads, COAL's, etc and haven't had the chance to load up anything exciting.  I hope to find some time this weekend to load up a few hundred rounds and get out and test it and see how she runs.  I feel a lot more comfortable with the Gen 3 and don't doubt it will perform flawlessly.

Very good to hear!

It sounds like it shouldn't have any issues. 

Fire it up this weekend!!

[The_Shadow]

Species, Glad that Glock made you "the customer", happy with the exchange and hopefully the Gen 3 will run right for you.
I really want to see Glock find the problem with the Gen4's, because many like the feel and use of the new back straps.
The Gen4's also had many new first time buyers interested in the 10mm in particular. 

[Species]

Congrats Species!  Question:  Does your Gen3 have the extended mag release that the Gen4's have?

The mag release is not ambidextrous (obviously) and it is different in look and feel than the Gen 4.  Not sure if it is considered "extended" or not.  I can post some pics.  It is quite prominent and easy to locate on the frame.

[Species]

Species, Glad that Glock made you "the customer", happy with the exchange and hopefully the Gen 3 will run right for you.
I really want to see Glock find the problem with the Gen4's, because many like the feel and use of the new back straps.
The Gen4's also had many new first time buyers interested in the 10mm in particular. 

I really really really liked the Gen 4 for the back straps and the new stippling on the frame.  I do miss those features.    

The dual recoil spring was a waste as I ended up swapping it out almost immediately for a heavier setup.

[The_Shadow]

I would like to have seen if a non captive version, of the factory dual spring RSA would have worked, in the gen4.  I am still leaning toward the redesign of the frame, with the replaceable straps, as inducing a flex which may be causing the failures to feed properly with the higher impulse ammo. 

The non captive Wolff dual 21 lb spring set in my G-29 works very well and the G-20Sf has a non captive single spring also Wolff 22lb.   

[4949shooter]

Just to update everyone on this situation.  I finally got my new G20 Gen 3 a couple weeks ago from Glock.  They shipped it to my FFL with a few extra magazines which was a bonus.  It took Glock about 2 weeks to get the replacement out the door.  Not too bad all things considered.   Overall I have to say I am pleased with Glock and how they took care of me.  Not so pleased with the performance of my Gen 4, but Glock stood behind their product and made things right by sending me a Gen 3.  Will I buy another Glock.....probably not.  Am I happy with Glock and their customer service....yes I am.

The Glock armorer who was handling my case called me when they were shipping the pistol out to tell me he personally fired 100-150 rounds of the hottest stuff he could find and the replacement ran perfectly.  I appreciated that phone call.  He said 25 of the rounds he fired were Underwood 165 grains - that was all they had on hand.  The pistol was pretty dirty when I took it out of the box.  Not bad dirty, just looked like it had been to a good range session.  That made me feel better that Glock took the time to test it out with what little hot ammo they had on hand before sending it out the door.  There was not a scratch on the gun, just dirty.

I have not been out to shoot it with any hot loads yet.  I have only had the chance to shoot some Armscor range ammo and it worked great.  I burned through all my good stuff testing the Gen 4 with various springs, mags, followers, loads, COAL's, etc and haven't had the chance to load up anything exciting.  I hope to find some time this weekend to load up a few hundred rounds and get out and test it and see how she runs.  I feel a lot more comfortable with the Gen 3 and don't doubt it will perform flawlessly.

Glad they got you a Gen 3 replacement. My Gen 3 SF likes the Underwood 165 grain loads.

[PandaBear]

I had the slide lock back with 1 round left in in the mag (10% Wolff Springs) on a few occasions last night with my Gen 4 and Underwood 165 TMJ.

I ran some 40 S&W right afterwards and had 0 issues. It's strictly a range gun, but I will likely give Glock a call to try and get some #4 followers.

[radiotom]

Species, have you been able to shoot your new Gen 3 with hot loads yet?

[Species]

Species, have you been able to shoot your new Gen 3 with hot loads yet?

Not yet...  :'(  Life has been a little chaotic lately. Hoping to get out tomorrow for a quick trip to the range.

[radiotom]

I'm just curious because I used to have a Model 20 Gen 4 that Glock swapped out too. My Gen 3 SF has been great totally stock and also with my KKM 4.6 barrel and Wolff guide rod + #22 spring.

[Species]

Species, have you been able to shoot your new Gen 3 with hot loads yet?

Got the new Gen 3 G20 out yesterday and it seems to be working great.  I shot 50 rounds of 180 gr GDHP's loaded 9.3 grains of Longshot.  Not super max load, but getting up there.  It fed those 100%.  the Gen 4 would not take that exact load.  This was with my 22 pound spring and KKM Barrel.

I also shot 50 rounds of 180 grain Precision Delta JHP loaded to 1050 fps just to test out a load for my wife to shoot.  I put the 24 pound Wolff spring in and it was 100%.  I was pleased it fired the "weak" loads with the strongest spring you can purchase from Wolff.  The brass still ejected 5-10 feet and I had no issues with short stroking.

The day was not without issues.......   I had loaded up some 200 grain Double Tap WFNGC to near max load using 800-X.  I loaded them to 1.250" COAL.  These rounds caused FTF's about 50% of the time.  It did this with both the stock barrel and the KKM.  I also tried the stock spring, a 22 pound spring, and 24 pound spring.  All had similar 50% FTF ratios.   I am pretty sure it was the bullet and not the gun, spring, or barrel.  I have always been concerned about how big the meplat is on the doubletap WFNGC bullets.  There is not alot of taper on the bullet and I am sure that is what is causing the issues.  I may have to find another hard cast bullet with more taper.  I think Buffalo bore uses a hard cast with more taper and may feed better.  I think the Double tap bullets are actually made by Beartooth and sold by doubletap under their label.

I shot about 150 rounds and it was 100% with the loads it likes.  It hates the WFNGC.  I am pleased with the results thus far.  I will load up a few other recipes and get them a little closer to max now that I have a comfort level with the gun.  I didn't want to go out and go full tilt max load on my first day out with the new gun.  I will keep you posted, but I think the Gen 3 is a winner.