I hadn't shot my G20 for over a year, but recently went out with a friend to try his new rifle build and figured I would bring my G20 along to try some Underwood loads I had never fired.
The Underwood loads were the 155gr 1500 fps ones. The first few shots went OK and were on target.
On the fourth shot, the magazine dropped (or was forced) out of the gun. I made absolutely sure the magazine was seated rock-solid and tried again, and it happened again. My buddy was pretty sure I was inadvertently hitting the mag release button while shooting, but I carefully demonstrated to him and to myself that this was not the case. It happened with 3 magazines, including when my friend tried it. Of course, he was sure it was me until the same thing happened to him. It appeared to us that the magazine was being forced out of the mag well. What would do that?
The issue did not present itself when using the Hornady XTP 180gr 1180 fps load. This load has always run 100% in this gun.
This gun never exhibited such an issue over the hundreds of rounds I shot out of it in early 2015, only a few misfeeds with hotter Underwood ammo. But this was the first time I had tried this exact Underwood load.
The barrel is factory and so are all other parts. Only the sights were replaced with a tritium set.
Interesting to say the least, did you inspect the fired brass for damage or leakage?
The mag release catch or spring may have gotten damaged somehow or the magazine catch notch itself and it is unlatching and sliding free under heavy recoil. Compare things to other magazines and the latch itself.
(https://www.northwestfirearms.com/attachments/218111/)
Have a real close look at the ejected brass. Look for any case head separation, usually at the upper angle of the extraction groove, or at the top of the web. Anything that looks like a crack or split indicates escaping gas. The magazine well should also have some soot and/or powder residue, if that's the cause. It doesn't take much gas to blow out the Glock magazine, which is a good thing (it would split the frame and/or blow out through your hand, otherwise). Check this first, as it is a dangerous condition. If this appears to be a problem, it wouldn't be the first complaint of pressure issues with early UW 155's. More recent loads are reduced, significantly.
Definitely check the magazine catch, specifically for rounding-off or chipping at the upper side of the inner radius, opposite the button end. Check the mags for similar on the right/upper area of the catch-notch. If this is evident, reverse the button and try again. This will make it a "lefty", but will work for testing.
Appreciate the fast, good responses!
The last week and a half have been busy with camping, traveling, other gun projects, etc., but I saved all the brass from that range session for later inspection. I have had a look at the mag catch, mag catch spring, mag catch indents on the magazines. The mag catch and spring look normal but one of the mags exhibits rounding/erosion at the top of the indent.
I have new spare mag catch parts to swap in and I have new magazines and a KKM barrel on order.
Will definitely have a look at that brass ASAP.
Thanks again gentlemen!
My Underwood brass shows no signs of severe distress, such as case head separation. However, it bulges at the rear more than the brass from the milder Hornady loads. The bulges in the Underwood brass are visible with my reading glasses and the calipers show that the high spots of the bulges are bigger than 11mm, whereas the entire length of the Hornady brass stays below 11mm in diameter. This did not surprise me. Is it indicative of inadequate support in the Glock factory barrel? The bulged areas would be inside the chamber when the round is in it, so maybe the chamber on that factory barrel is too loose near the mouth.
There is no more soot/residue in the mag well than I would expect.
Could the frame be battered so hard by these loads that it rattles the mag, mag catch and spring enough that the mag drops out?
It seems like I'm just a better-supported barrel and/or a stronger recoil spring (these are in the mail) away from avoiding this issue. Maybe it's not even the barrel but I know I will feel better with a barrel that provides more complete support.
I have fired all the hottest loads from Underwood and Buffalo Bore through both of my Glock 20's (a Gen 3 and a Gen 4) without issue.
Your Gen 4 barrel should be fine as far as support goes. I would look for another cause to this magazine drop issue. Perhaps the mag is not being seated fully, or the mag catch spring is on the weak side.
Thanks. For sure the mag was seated fully in all cases. Am a competition shooter and know that I know how to make sure a mag is seated, plus my buddy cross-checked, plus I never had the issue until shooting the one particular load.
Mag catch spring could be weak I suppose but it was never a problem before.
I thank you kindly for sharing your thoughts to help me problem-solve.
Increased slide velocity with the new load along with a weak mag release spring could be your problem.
I suspect a it's standard-strength mag release spring, just not up to the chore of keeping the mag release in its proper place when the recoil spring isn't strong enough to prevent battering.
I recently received some recoil springs to try, including a Wolff 24-lb recoil spring. It's in the gun now, waiting for me to try it.
Update on the Gen 4 G20
I was able to go out and try the gun with the KKM barrel and a Wolff 24-lb recoil spring, using 150gr (not 155gr) Underwood XTP loads stated to shoot at 1,500 fps. I also shot about 70 rounds of Underwood 180gr XTPs shown on the box to move along at 1,350 fps. So these are pretty hot loads.
I also shot about 30 rounds of Hornady 180gr XTPs, advertised at 1,180 fps. These shot reliably in the gun from the beginning, and did so once again. I'm happy these will cycle the gun with the 24-lb recoil spring.
The mag dropout issue appears to have gone away. I should note that I now have an aluminum mag catch in the gun. I don't like how extended it is because now the chance of operator-induced mag droppage is greater. I can reshape the external button or go back to a factory part, and I'd even consider cutting down the factory mag catch button somewhat. I personally do not need that big of a button since my thumbs are not short.
There were a couple of failures to feed early on, which I attribute to the new barrel and a somewhat dirty and dry gun (my bad). Things smoothed out as I got a few mags into the shooting.
A new issue that emerged is the slide locking back when the last round is at the top of the magazine. This didn't occur when loading only 5 rounds in a mag, but only occasionally when loading 10 or more rounds in the mag. My last string was with a full mag +1 in the chamber, with the Underwood 180gr XTPs. All rounds fired except for the last one which sat on top of the mag with the slide inexplicably locked back. A quick rack-bang was successful in every case where this happened. I'll sort this out eventually I'm sure.
Now that I've cleaned the gun well, I'll report back after the next range session.
The Good
The trigger is really pretty good. I have not done anything to it so it's supposed to be around 5.5 lbs, but it feels lighter and is not as mushy as other Glock triggers I've used.
The gun is comfortable to shoot with the hot loads. I shot whole magazines one-handed, rapidly, and was not bothered at all. I won't claim I can completely contain muzzle flip but still, the gun is quite controllable and causes no pain. I use roughly the same grip pressure I use when shooting mild .45 ACP out of a 5" 1911, and it is enough.
I was shooting at a variety of targets and was hugely pleased how I can put bullets where I want them to go. The 70+ competition matches I've shot have helped my overall handgunner skills, and it is satisfying to see them show up with the G20 shooting hot loads.
Glad you got it sorted out. The 24 pound spring helped my 20 as well with certain loads.
I purchased a used G40 early this year that was only a few months old. Using the Underwood 140 Xtreme Penetrator velocity was close to 1700 fps and the brass badly bulged. The ammo while hot looked fine when shot in some other 10mms including a G20. In addition the trigger was not resetting properly.
Upon pulling the gun apart the previous owner had put in a Ghost 3.5 connector and parts. I contacted the seller who "thought" he had included the original factory parts (gotta love home gunsmiths). Once they were reinstalled all the problems went away. I then added a Lone Wolf stainless steel guiderod and increased power recoil sping and it even shoots better now.
Apparently the reduced power springs were allowing the slide to unlock sooner then the pressure dropped causing the bulges.
Bob
Having had a chance to read more material from other G20 Gen 4 owners, I see that my issues are not unique to me and this gun.
I'd be pleased as punch if there were a simple remedy for the last round not feeding. I've read about guys reshaping their slide stops, trying different slide stops, using stronger mag springs, etc., with varied success.
Clearly Glock did not set these guns up to handle anything beyond medium-hot 10mm, and they seem to want to stay out of the business of helping Glock owners validate problems they have with the hotter loads.
OK don't know if this applies.
I tried field stripping that turned out to be almost impossible to get the slide off but some how it works sort ofishly.
But to get the slide on, I have to push the "Trigger bar?" all the way forward for the trigger to go forward before I can rack the slide all the way back to reset every thing. It won't go back all the way it stops even with the back of the gun.
No this gun hasn't even been fired, I just got it yesterday!
OK after take apart where it seems to be a PIA slide removal that can be done after a few attempts each, seems some weird trick to get it done on this gun.
Then I got the slide to rack back several times to reset and lock up. But a few times I had to do the push the bar to push the trigger all the way forward to get the gun to rack back to reset. Trigger resets and the gun operates normally after that. I have a feeling this isn't normal?
Edit: FOUND SOME THING!
OK...U-TUBE to the rescue! Its the bump on the trigger bar! Move slide to left when moving back then move back right.
https://www.youtube.com/watch?v=Mj8Qt8ofCAw
Still a PIA to field strip still...
Now that I find its a few years old problem and commonish it seems...mines a still a keeper! ;D
Quote from: Roguer on September 13 2016 09:50:02 PM MDT
OK after take apart where it seems to be a PIA slide removal that can be done after a few attempts each, seems some weird trick to get it done on this gun.
Then I got the slide to rack back several times to reset and lock up. But a few times I had to do the push the bar to push the trigger all the way forward to get the gun to rack back to reset. Trigger resets and the gun operates normally after that. I have a feeling this isn't normal?
Edit: FOUND SOME THING!
OK...U-TUBE to the rescue! Its the bump on the trigger bar! Move slide to left when moving back then move back right.
https://www.youtube.com/watch?v=Mj8Qt8ofCAw (https://www.youtube.com/watch?v=Mj8Qt8ofCAw)
Still a PIA to field strip still...
Simply put, there's something wrong with your pistol, or your familiarity with them. Visit an armorer or your LGS for a closer look.
Agree.
Glocks are the easiest gun to strip and reassemble I own, and I own a fair few.
I have to agree, I currently own 4 Glocks, and have had as many as 7. They are among the easiest to strip and re-assemble.
Well this one doesn't disassemble easy and now it has a new quirk.
Slide going almost all the way back and stopping 1/4" from the rear, then a trigger pull seems to set it then the slide goes all the way forward. And this one wasn't trying to dissemble it. How ever there was an attempt right before racking the slide back to reset the trigger that didn't work.
That definitely sounds wrong. Make sure the trigger/ejector group assy rear pin is in place. I'd remove and replace it, to make sure the assy is fully seated and the pin isn't broken. If it's missing or broken, that's about the only thing I can think of that would cause what you describe, short of a major component actually bent or broken. The trigger shouldn't reset until about the last 1/4" of forward travel. If it's resetting or interfering before that, something's outta whack, or broken.
Agree...Your gun sounds broken and potentially unsafe.
My advice is to send it back to Glock. They will make it right for you.
Roguer, something is amiss with the G-20. What generation is it? 3rd? 4th? If this is a factory new gun call Glock to return to Glock!
Just to be sure, before you try to remove the slide, did you pull the trigger to decock the striker?
Is your RSA (recoil spring assembly) factory?
If you have the gun apart, inspect the recoil assembly for damage, the spring could be binding up toward the end of slide retraction. Have you tried the slide on the frame without the RSA inside to see if there is any binding or stopping short?
Inspect the locking block where the barrel sits, for bent or broken damage.
What about the plunger in the slide, does it move freely? Is it binding? If binding you might need to remove the slide cover plate (carefully because there is the spring and rod for the extractor under some pressure). Remove the striker and inspect all parts for incorrect assembly or damage.
Glocks are fairly simple guns with few parts...
Quote from: The_Shadow on September 15 2016 08:25:55 AM MDT
Roguer, something is amiss with the G-20. What generation is it? 3rd? 4th? If this is a factory new gun call Glock to return to Glock!
Just to be sure, before you try to remove the slide, did you pull the trigger to decock the striker?
Is your RSA (recoil spring assembly) factory?
If you have the gun apart, inspect the recoil assembly for damage, the spring could be binding up toward the end of slide retraction. Have you tried the slide on the frame without the RSA inside to see if there is any binding or stopping short?
Inspect the locking block where the barrel sits, for bent or broken damage.
What about the plunger in the slide, does it move freely? Is it binding? If binding you might need to remove the slide cover plate (carefully because there is the spring and rod for the extractor under some pressure). Remove the striker and inspect all parts for incorrect assembly or damage.
Glocks are fairly simple guns with few parts...
Good points, but I was under the impression this is a new, unfired G40.
I didn't see which model he had...Same stuff would apply to any and all of the Glocks...
Oops sorry this a 40.
Solved my Problems the American Way!
Took it back to my LGS (Local Gun Shop) (I have been getting guns from him for years) and explained every thing and the problems and since it wasn't fired he gave me a full refund! He didn't have another Glock 40 or I would of traded and got another one that was probably the only last one in the area. This turned out to be a Glock Stocker so I...
GOT GLOCK (40) AGAIN!
The LGS I got the first one from had people try disassemble it, most could do it mostly but some took some tries, one got it both attempts. But I tried to stress the other slide locking and such, don't know of they just saw it as me as an ignoramus and they agreed it seemed fine. I relayed a few things I got from here and a few other places so they can check it out. But every one's advice here helped me out a lot and thanks to my LGS standing by their products I was able to get another Glock 40!
I posted here in the Gen4 Glock 20 as the two are about the same.
Gotta love those home gunsmith.. If you are not an armorer do not take the gun apart farther than advised. Always screwed up with these aftermarket parts everything has to be fixed with all these extra parts that are not made for the glock. I've had stock glocks for last 20 years and I've had awesome luck. I have a Glock model 40 now that will blow through any rounds that I can get my hands on like Buffalo Bore Underwood or even my really stuffed up and loads..
Enough with the home gunsmith bashing. Being a certified Glock armorer isn't exactly akin to brain surgery.
The trigger reset problem is an easy fix. Try bending the disconnector to a little bit over ninety degrees on the inside of the big L. 95° works great.
Every owner should know how to disassemble their slides. The biggest cause of failure to fire in well used striker fired pistols is poorly maintained striker channels. It is also the only way to disassemble the pistol without pulling the trigger.
Some difficulty can be experienced in disassembly due to the recoil spring assembly shifting out of place. I find this on my Gen 3's alot. I just ensure the striker is down and lightly tap the slide with the heel of my hand while holding down the slide stop tabs.
FWIW, what you experiencing when reassembling is normal. There are a few ways to get the slide to go on. (in fact, I hadn't heard of the way you watched on youtube...)...
Method #1. While the slide is removed but assembled (and ready to go back onto the receiver ...), depress the firing pin safety plunger in and push the rear of the striker arm (the one that makes contact with the cruciform plate below during trigger operation) forward towards the muzzle of the firearm until the firing pin protrudes from the breech face, then reassemble as normal.
Method #2: The trigger should be in it's rearward most position before removing the slide, locked safely back. When the rear of the slide and rear of receiver are lined up (but otherwise "locked / stopped" so that reassembly is prevented (the condition you describe in your post above)... and WHILE continuing to put rearward pressure on the slide in an effort to 'fully' reassemble slide to receiver, use your third or fourth hand (lol) and push FORWARD on the trigger (which is locked in rearward position still) and the slide should 'click' in and successfully mate to the receiver.
Annnywayyys.... yes, what you experienced is normal for Gen4 firearms that have aftermarket triggers in them, it would seem.
I'd love to say my G20 issues are entirely sorted out. Seems the gun is suffering from a weakened mag catch spring. Have to be careful when switching out mag catches not to flex that little rod spring so much that you put a bend in it -- very easy to do. I ordered replacements.
A new mag catch spring was the ticket. Perfect function last Saturday with 15+1 rounds of Underwood 150gr JHP at 1500 fps! In case anyone is wondering, I'm using a 24 lb recoil spring.
Thanks for the feedback. That is good news. I always hate to hear about a Glock that is sick.
Quote from: GunBugBit on August 21 2017 08:29:20 AM MDT
A new mag catch spring was the ticket. Perfect function last Saturday with 15+1 rounds of Underwood 150gr JHP at 1500 fps! In case anyone is wondering, I'm using a 24 lb recoil spring.
If your G-20 is gen 4, what is the make of the recoil 24 lb spring setup???
Good question and I am not good at remembering where I order all of my parts from. With my 1911s, I can usually recall where I got my parts, but with Glocks and ARs, not so much. I had to find a company selling a kit including the little adapter for the forward slide hole. If I come across where I ordered the rod/spring/adapter from, I'll post it here. I think I got the spring from one company and the rod and adapter from another company.
At the risk of being incorrect, I'm going to say I got the spring from Wolff. I will have to think harder or dig up where I got the rod and adapter.
Quote from: sqlbullet on August 21 2017 09:04:10 AM MDT
Thanks for the feedback. That is good news. I always hate to hear about a Glock that is sick.
Thanks!
Quote from: GunBugBit on August 21 2017 10:11:43 AM MDT
At the risk of being incorrect, I'm going to say I got the spring from Wolff.
One thing I can tell you, the spring is not flat coil but round coil.
Poking around just now, I see that Glockmeister sells a 24-lb flat coil captive spring on a steel rod.
http://www.glockmeister.com/Glockmeister-Stainless-Steel-Recoil-Spring-Assembly-for-Gen-4-20-21-40-41/productinfo/G4SS20CS/
I have a couple 22-lb versions of this but a 24 is what's in my gun right now. Also have a 20-lb flat spring.
Still don't know for sure the source of my non-captive round coil setup. The rod has a screw in the end so I can change out springs (a non-captive setup). I'll take a pic of this if I think of it, a few might be interested.
I would go to lower spring weights if shooting the milder 10mm, but I want to shoot mainly Underwood and if 24-lbs is what works for those loads, I'll keep it in the gun. Next session, I might see if the 22-lb works.
Quote from: GunBugBit on August 21 2017 10:30:00 AM MDT
Quote from: GunBugBit on August 21 2017 10:11:43 AM MDT
At the risk of being incorrect, I'm going to say I got the spring from Wolff.
One thing I can tell you, the spring is not flat coil but round coil.
Poking around just now, I see that Glockmeister sells a 24-lb flat coil captive spring on a steel rod.
http://www.glockmeister.com/Glockmeister-Stainless-Steel-Recoil-Spring-Assembly-for-Gen-4-20-21-40-41/productinfo/G4SS20CS/
I have a couple 22-lb versions of this but a 24 is what's in my gun right now. Also have a 20-lb flat spring.
Still don't know for sure the source of my non-captive round coil setup. The rod has a screw in the end so I can change out springs (a non-captive setup). I'll take a pic of this if I think of it, a few might be interested.
I would go to lower spring weights if shooting the milder 10mm, but I want to shoot mainly Underwood and if 24-lbs is what works for those loads, I'll keep it in the gun. Next session, I might see if the 22-lb works.
This is the spring I sometimes use in my Gen 4.
Just really pleased that the G20 is now what I hoped it could be.
Quote from: GunBugBit on August 21 2017 10:30:00 AM MDT
Still don't know for sure the source of my non-captive round coil setup. The rod has a screw in the end so I can change out springs (a non-captive setup). I'll take a pic of this if I think of it, a few might be interested.
I would go to lower spring weights if shooting the milder 10mm, but I want to shoot mainly Underwood and if 24-lbs is what works for those loads, I'll keep it in the gun. Next session, I might see if the 22-lb works.
If your rod has a screw then it makes it captive.... Non-Captive the spring or springs will slide off the recoil rod or rods without removal of any captive device...
My 20 SF is setup with the Wolff non captive recoil rod and 22lbs spring, also have the 20lbs and 24lbs springs. I also like the fact that the non captive setup is holding the slide closed, requiring slightly more force to pull from battery.
If I am testing heavier loads, I will run the 24 lbs, however the 22lbs is working for the 10mm, 40S&W and 9x25 dillon loadings.