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Mountain10mm
06-27-2011, 12:56
I know other people have had the same issue. I could really use the help of an internal ballistician to figure this one out.

I have two G20's one Gen3 and one G20SF, both currently stock guns, and the problem happens with both of them. Here's the problem: with any full power load (180 or 200gr. above 1200fps., verified with a chronograph) the slide fails to catch the next round in the magazine at about the sixth or seventh shot in a 15 round magazine. In other words, at about the 7th round in a 15 round magazine, the slide will eject the empty case, but catch the next live round in the magazine on the cartridge wall between the rim and case mouth. The live round "stovepipes" vertically with the nose of the bullet jammed against the top of the chamber. It doesn’t' make any difference what magazine I use (I have about 10 of them- old and new ones) nor does it make any difference what ammo I use provided it really is full power - chronograph verified. (Some ammo. manufactures brag about full-power loads, but the chronograph indicates otherwise.) CCI blazers, Hornady 180gr., Remington UMC 180 gr., all function flawlessly.

I've tried stiffer recoil springs all the way to 24#s and the problems gets worse. The same problem happens with a 5.5” aftermarket Jarvis barrel. The problem won’t happen if I rapid fire the pistol…pretty much as fast as I can. If I slow fire the gun jams almost guaranteed at about round 6, 7 or 8.
In diagnosing the problem, and speaking with a Glock technician, it appears slide speed could be an issue. One thought is that a stronger magazine spring would help. (They are on order and should be here within a day or two – though others with the same problem have stated the magazine springs helped, but did not solve the problem.)

I am also thinking that it could be the slide is not going back all the way and therefore not able to catch the rim of the next round. In “playing” with the gun using a spent reload case (180 XTP bullet at 1250fps.) and live rounds in the magazine, it takes an extraordinary amount of effort to eject the spent case from the chamber and rack the slide all the way back. Here’s where a ballistician could help. Is it possible that the higher pressure from the full power load is keeping the slide and barrel locked longer (i.e. the slide can not open due to the super-expanded shell in the chamber) and when it does open it doesn’t have enough energy to push the slide all the way back? Or is it that the expanded case (very slight bulge) is catching on the next live round and slowing the slide down? Why does it happen only in slow fire? Does the brass have more time to expand due to a heated barrel and therefore create a tighter fit…again slowing down the slide while trying to extract the empty case?

Please people, do not tell me this is limp wristing, or bad ammo., or I need a stiffer recoil spring. I’ve tried all to isolate all of those conditions and the problem still happens with a weak wrist or fully braced, reloaded ammo. or commercially manufactured, and with various recoil springs all the way to 24lbs.

I could shoot the 10mm target ammo. in the gun, but then why have a 10mm?
Thanks for all your help.

cowboywannabe
06-27-2011, 13:18
my G20 and 29 are stock EXCEPT for the 22 pound recoil spring assy.

stock mags, stock barrels....shoot DT and CB without a hitch though they claim to be full power they actually are mid powered in real life from my gun.

Mountain10mm
06-27-2011, 13:23
Double Taps 200gr. FMJ or XTP (when they actually used the XTP bullet) averaged right around 1100fps out of my stock G20 and worked flawlessly. Problem is DT advertised this round at 1250fps. Like you said this is a mid-power round - no where near full power.

I appreciate your input. Thanks.

wildehond
06-27-2011, 13:27
It sounds like the culprit is probably the magazine spring or follower. How old is the magazines and which vintage. It might be worth checking with Glock if there was not a problem with either of those with your model.

It is seems the magazine is pushing up the nose of the round and the back does not have enought time to move up to catch the slide as it is coming forward. I have seen this kind of malfunction with 1911's and bad followers. So this is what I would check first.

Burien
06-27-2011, 15:22
Main recoil spring is strong and magazine springs are weak, get stronger magaine springs or factory recoil spring.

My G-29 has 23 lb spring, and will not feed G-20 mags at all, maybe get 1-3 rounds out before the rounds "nose dive" into the feeding ramp or mag body.

Please let us know what you do.

_The_Shadow
06-27-2011, 16:19
It would seem that the magazine spring is not pushing up fast enough to feed the ammo due to the impulse and slide travel. Be aware of your ammo's COAL as 1.250" is usually better for feeding issues. Longer cartridges can bind inside the magazine well if even for a split second. IMO the 24lb spring is probably too strong and makes racking the slide tough which can hamper defensive actions in stressful situations.

As was mentioned the cartridge on top may could be sliding around under recoil before the mag spring pushes it into position. Try tapping the magazine to seat all cartridges fully to the rear of the mag.

Best of luck!

Mountain10mm
06-30-2011, 16:28
Possible solution? I don't want to curse myself, but I replaced the magazine springs in three magazines with Wolff +10% springs and the gun worked flawlessly. I only tried one magazine and only had time for about 40 rounds, but there were no jambs. However, the magazine follower caused the slide lock to engage with one round left in the magazine. I can live with that...I still have 14 rounds of full power 10mm - assuming this is the fix. This weekend I'll try a few more rounds in the other magazines and see what happens.

ModGlock17
06-30-2011, 16:57
I had the same jamm issue when my G20 was newer. It would jamm like you described on the second round, with both mags that came with the gun.

But somewhere after 300-400 rounds it went away. Now I did plenty of things to the gun right around that time, like
-polish the chamber ramp a little bit making it slickier
-polish and oil/grease the four guide tabs so it slides better
-lightly oil the rag and wipe it on the inside of the mags where the plastic would slide against.

Not sure what caused it, but it went away. I haven't seen any correlation with the power of the loads as yet.

It could simply meant that the gun needed to break-in a little bit more, so any mod I make right around that time would incorrectly get the credit for "solving" the problem.

headblade
06-30-2011, 19:04
My name is Jeff and I too am a Glockoholic. I have had a lot of feeding issues lately with my G-20. I been reloading a lil on the warm side very near max listed in hornady book with 180 gr projectile using 800- x. (avg 1370 FPS using KKM 6") I thought my mags were the problem so I switched out my stock magazine springs with the 10% extra power wolffs (on 4 mags) and even assumed I would need to up the recoil spring strength to 22# and 24#. And so begins the testing. I was getting nose dives (back into the mag), nose ups, and even sometimes the spent case would not clear the slide fast enough and not stove pipe but would get pinched between the barrel hood and upper portion of the breech face for a split second damaging brass but in most instances not hindering function but dropping the brass nearby my feet. These problems were happening with both stock barrel and my 6" KKM. (FYI I use KKM 6" only now and in the test listed below) The last time I was at the range I took 200 rounds of reloads all L.E. Wilson Max guage tested and began to shoot. I think it was as early as the second shot I got a FTFeed. The previous shoot session a weekend earlier I had quite a few FTFs and so this frustrated me. With nothing else to try I just ripped out the 22lb. recoil spring and put the stock Glock 17# in and fired about 2 magazines worth with ZERO problems. I then stepped it up and put the 19# spring in and finished about 180 rounds and had one more FTFeed in that whole bunch. At this point I'm inclined to think that I jumped onto the Need A Stronger Recoil Spring Boat way too soon. Also, maybe my KKM 6" needs a different type of love than the stock barrel and so if I have the patience perhaps I will test to see what lb. spring my stock barrel will be comfortable using. I think I would get 100% reliability out of an 18# spring if they make that one. If I can't find one I'll just shoot the $nit out of my 19# and beat it into submission. Maybe the next few weeks I'll pump out another 2 or 3 hundred rounds with the 17lb spring and see what happens. If my memory serves me correctly the 24# spring would produce a FTF every other shot. So, the stiffer the spring the more FTFs I seem to experience.
Yes, the brass flies 15+feet, the burrs on the rim take a little filing down (I have a burrphobia), and the pistol might be battered a bit more than using a stiffer spring but my pistol seems to have transformed from a paper weight into a reliable shooter.

oceanbob
06-30-2011, 20:07
Good post above...^^^^

I run my normal 17 pound spring without issues. I also have a 20 pound spring that runs 100%. Anything higher in weight does impact reliability.

My vote is FACTORY all the way. If you're worried about banging up the slide then buy a plastic buffer. I am not worried. I want a weapon the runs 100%. :supergrin:

I did change my mag springs to the wolff plus 10% springs. They 'seem' just like the Glock 22/35 mag springs, which are considered stronger than the GLOCK 20 mag springs. (one extra loop..?)

When your running these 10MM hot loads and shooting fast, you really should have strong springs so the ammo can keep up. Moving all those rounds (in a 15 or more magazine) UP fast enough requires a plus 10% spring. When I change out the springs, I also change out the FLOORPLATE to Orange. That way I know that MAG has the super duty spring.

Be well my friends and have a great 4th of July..!

Bob

http://i54.tinypic.com/kdwy7t.jpg

http://i53.tinypic.com/13zcxv6.jpg

HAMMERHEAD
06-30-2011, 20:19
Cool 29!

21Carrier
07-01-2011, 01:59
Headblade, I think you're right about the spring. I bought 17lb, 21lb, and 23lb Wolff springs for my G29. I have only used the 23lb spring (to reduce battering) at the range, and carry 100% stock. While mine has been perfect, except for a few pieces of brass getting pinched like yours on a single, REALLY hot 800-X load, I figured out that G20 mags don't like the 23lb spring. I was having lots of FTFs with it. I thought it was just the mag since it was an OLD NFML G20 mag. Then I accidentally left my stock spring in and tried the G20 mag. It worked great! I just now realized that must have been what did it.

I agree that lots of people jump on the stronger spring bandwagon too quickly. It seems it's an unspoken myth around here that they are NECESSARY to shoot hot loads. They really aren't. And while my 23lb spring has been flawless with ANY load, bunny-fart or nuclear, and the stock mags, it just doesn't mesh well with the G20 mags. I will keep using it, but I think everyone needs to realize it may affect reliability, especially with the G20. I think the Wolff +10% mag springs help, but the stiff recoil springs just cause the slide to close too quickly for good feeding. If you add a tighter, aftermarket barrel into the mix, I think it will just complicate things more.

Just realize, the springs are great for reduced battering, keeping your brass in THIS county, and they reduce the damage done to brass with serious loads. But for reliability, you will get no better than 100% factory Glock.

Also, some advice for new G20/29 owners modifying their guns: I learned this lesson while modifying cars, and while they are MUCH more complex, this still holds true. When you start modifying your gun/s, do ONE piece at a time. If you order a barrel, recoil spring, and mag springs all at once, then INSTALL them all at once, if the gun starts acting up, you will have no clue which caused the problem. If the gun is working perfectly stock, add one part, and run at least 100 rounds to test for function. If it's good, move on to the next part. If not, set that part aside, return to stock, then test the next part. By doing this, you will know exactly which part is causing your troubles. Then you can work out the solution.

oceanbob
07-01-2011, 11:12
Good advice.!


Headblade, I think you're right about the spring. I bought 17lb, 21lb, and 23lb Wolff springs for my G29. I have only used the 23lb spring (to reduce battering) at the range, and carry 100% stock. While mine has been perfect, except for a few pieces of brass getting pinched like yours on a single, REALLY hot 800-X load, I figured out that G20 mags don't like the 23lb spring. I was having lots of FTFs with it. I thought it was just the mag since it was an OLD NFML G20 mag. Then I accidentally left my stock spring in and tried the G20 mag. It worked great! I just now realized that must have been what did it.

I agree that lots of people jump on the stronger spring bandwagon too quickly. It seems it's an unspoken myth around here that they are NECESSARY to shoot hot loads. They really aren't. And while my 23lb spring has been flawless with ANY load, bunny-fart or nuclear, and the stock mags, it just doesn't mesh well with the G20 mags. I will keep using it, but I think everyone needs to realize it may affect reliability, especially with the G20. I think the Wolff +10% mag springs help, but the stiff recoil springs just cause the slide to close too quickly for good feeding. If you add a tighter, aftermarket barrel into the mix, I think it will just complicate things more.

Just realize, the springs are great for reduced battering, keeping your brass in THIS county, and they reduce the damage done to brass with serious loads. But for reliability, you will get no better than 100% factory Glock.

Also, some advice for new G20/29 owners modifying their guns: I learned this lesson while modifying cars, and while they are MUCH more complex, this still holds true. When you start modifying your gun/s, do ONE piece at a time. If you order a barrel, recoil spring, and mag springs all at once, then INSTALL them all at once, if the gun starts acting up, you will have no clue which caused the problem. If the gun is working perfectly stock, add one part, and run at least 100 rounds to test for function. If it's good, move on to the next part. If not, set that part aside, return to stock, then test the next part. By doing this, you will know exactly which part is causing your troubles. Then you can work out the solution.

gator378
07-01-2011, 13:52
I know other people have had the same issue. I could really use the help of an internal ballistician to figure this one out.

I have two G20's one Gen3 and one G20SF, both currently stock guns, and the problem happens with both of them. Here's the problem: with any full power load (180 or 200gr. above 1200fps., verified with a chronograph) the slide fails to catch the next round in the magazine at about the sixth or seventh shot in a 15 round magazine. In other words, at about the 7th round in a 15 round magazine, the slide will eject the empty case, but catch the next live round in the magazine on the cartridge wall between the rim and case mouth. The live round "stovepipes" vertically with the nose of the bullet jammed against the top of the chamber. It doesn’t' make any difference what magazine I use (I have about 10 of them- old and new ones) nor does it make any difference what ammo I use provided it really is full power - chronograph verified. (Some ammo. manufactures brag about full-power loads, but the chronograph indicates otherwise.) CCI blazers, Hornady 180gr., Remington UMC 180 gr., all function flawlessly.

I've tried stiffer recoil springs all the way to 24#s and the problems gets worse. The same problem happens with a 5.5” aftermarket Jarvis barrel. The problem won’t happen if I rapid fire the pistol…pretty much as fast as I can. If I slow fire the gun jams almost guaranteed at about round 6, 7 or 8.
In diagnosing the problem, and speaking with a Glock technician, it appears slide speed could be an issue. One thought is that a stronger magazine spring would help. (They are on order and should be here within a day or two – though others with the same problem have stated the magazine springs helped, but did not solve the problem.)

I am also thinking that it could be the slide is not going back all the way and therefore not able to catch the rim of the next round. In “playing” with the gun using a spent reload case (180 XTP bullet at 1250fps.) and live rounds in the magazine, it takes an extraordinary amount of effort to eject the spent case from the chamber and rack the slide all the way back. Here’s where a ballistician could help. Is it possible that the higher pressure from the full power load is keeping the slide and barrel locked longer (i.e. the slide can not open due to the super-expanded shell in the chamber) and when it does open it doesn’t have enough energy to push the slide all the way back? Or is it that the expanded case (very slight bulge) is catching on the next live round and slowing the slide down? Why does it happen only in slow fire? Does the brass have more time to expand due to a heated barrel and therefore create a tighter fit…again slowing down the slide while trying to extract the empty case?

Please people, do not tell me this is limp wristing, or bad ammo., or I need a stiffer recoil spring. I’ve tried all to isolate all of those conditions and the problem still happens with a weak wrist or fully braced, reloaded ammo. or commercially manufactured, and with various recoil springs all the way to 24lbs.

I could shoot the 10mm target ammo. in the gun, but then why have a 10mm?
Thanks for all your help.

Had a similiar problem with the Glock 21. Changed the Mag spring with an IMSI spring and the problem went away.

headblade
07-02-2011, 19:20
Possible solution? I don't want to curse myself, but I replaced the magazine springs in three magazines with Wolff +10% springs and the gun worked flawlessly. I only tried one magazine and only had time for about 40 rounds, but there were no jambs. However, the magazine follower caused the slide lock to engage with one round left in the magazine. I can live with that...I still have 14 rounds of full power 10mm - assuming this is the fix. This weekend I'll try a few more rounds in the other magazines and see what happens.
Ever since I put the 10% extra powered magazine springs in I also noticed a lot of the times my magazine follower will activate the slide stop with one round still in the mag. I thought for a while that it was my thumbs activating the slide stop lever during recoil so I cut my thumbs off and it kept still happening! j/k But the last few times it occurred I tried pulling the slide back and it was indeed stopped by the mag follower. Usually that last round is push forward half the distance of the feed lips which seems to allow enough elbow room for the cartridge to maneuver a bit and allow a situation in which the mag follower is able to rise just enough to activate the slide stop lever. Before I forget I shot another hundred rounds today and started off with 20# recoil spring with immediate FTF. I think my G-20 hates anything other than stock recoil springs. It did just fine after I put the 17# factory spring in. My 29 seems to be less finicky. But , then again I havn't fired my 29 as much as my 20 so maybe ugliness hasn't had much the oppertunity to rear its face.
Good advice 21. I did make the mistake of buying an aftermarket barrel, xtra powered mag springs, and xtra powered recoil springs and put them all together and prayed. Too bad it can't be that easy 8p

Taterhead
07-05-2011, 09:57
I finally encountered failures in my G20 yesterday. 22# spring. It has been virtually flawless for thousands of rounds. 200 grain XTP right near 1200 fps. The first failure was a nose-up jam. I could tell that the brass was collected midway up the case rather than on the rim. I could tell by the impression on the case.

A round or two later, no jam. However: "click". No round collected at all. It happened one more time. Altogether there were three failures out of ten. I tried that mag with some lower-velocity stuff. No problem. The increased velocity of the slide return plus the high velocity recoil impulse from the XTP was obvoisly too quick for the mag spring.

It is probably time to swap mag springs. I am also going to order a 20# recoil spring. I am feeling like the return impulse from the 22# spring is a bit harsh the more rounds I get through it. I would also rather have a bit more frame bang than reduced reliability.

I don't want to mess with mag spring rates at this point. So I will see what a lighter recoil spring will do.

21Carrier
07-05-2011, 11:37
Taterhead, I have found that in my G29, the Wolff extra power springs are problematic with very hot loads and should ONLY be used for range use to reduce battering and brass flinging. I've had problems with my 23lb spring before, but two days ago, while testing my 155gr Silvertip carry loads, I accidentally left my 21lb spring in. The first mag had two failures to feed. I realized the 21lb spring was in there, swapped it for the factory spring, and had zero problems.

I have now come to the realization that the heavier springs are not reliable with hot loads. I actually think they are MORE reliable with low to medium hot powered loads, as they perform flawlessly. When you toss in the really powerful recoil impulse of especially hot loads, forward slide speed is just too much.

I am starting to think that we are all trying to getting a little too smart for our own good. Modifications are great for range use, but we need to remember that EVERY SINGLE PIECE of our guns were chosen by Glock for ONE reason: reliability. If a stronger spring was more reliable, they would have used it. If a tighter barrel was more reliable, they would have used it. I don't know why this is the second time I've had to learn this lesson. I went through it modifying cars, but I guess I thought I knew better than Glock. I remember thinking I knew better than Ford once. Then, while racing a Corvette in 5 degree weather, I maxed out my fuel injectors, shattered a spark plug, and melted an exhaust valve. Lesson learned. I like Glocks because they are reliable. Mine will stay 100% stock from now on, unless at the range.

GTRhino24
07-05-2011, 12:03
. I like Glocks because they are reliable. Mine will stay 100% stock from now on, unless at the range.

I second that. If my life is on the line, I'm rockin stock glocks. Back in the days before I modified them, I can't remember a single issue.

Taterhead
07-05-2011, 14:02
I second that. If my life is on the line, I'm rockin stock glocks. Back in the days before I modified them, I can't remember a single issue.


Thus far, I have had zero failures with the box stock setup. Probably 75% of the rounds through my gun have been with the stock setup. IDPA does not permit the use of a steel aftermarket guide rod, and I go with the stick setup for carry. For carrying in the mountains, I have been loading the 22# spring since I am running a fairly heavy and hot load for that. I am now going to re-think that.

Only with the 22# spring have I encountered failures. It is altogether now a total of five or less. One failure on a prior occasion was a stove pipe due to limpwristing caused by practicing from an odd angle from cover. I have not been able to reproduce a limpwristing failure with the stock spring weight.

21Carrier
07-05-2011, 16:55
Thus far, I have had zero failures with the box stock setup. Only with the 22# spring have I encountered failures.

Same here. I have never had a single failure with the stock setup. Even with that really hot 155gr/800-X load that's been problematic, the gun has never had a stoppage. I've had brass get crushed, but it kept firing. With the heavier springs, it jams with that load. Also, with my old NFML G20 mag, the gun only works stock. The heavier springs cause jams with the G20 mag.

From now on, the ONLY time I'll ever use the heavy springs is at the range. Maybe I'll try the stronger magazine springs and see if that works, because I would REALLY like to use the heavy springs all the time to reduce battering and keep the round in the chamber longer.

Mountain10mm
07-06-2011, 10:32
Did some more testing this last weekend with the Wolff +10% recoil springs and they were great the first time the magazine was loaded. But, with subsequent magazine loadings, the problem reappeared. UGH! It was definitely less frequent than with stock magazine springs, but the magazine would lock the slide back with one round left in it every time. (That doesn't bother too much though.)

Back to the reloading bench... I reduced the powder charge I have been using by .1 grain increments until the gun would shoot a magazine flawlessly. (The gun is stock except for the magazine spring.) The winning load yesterday was 13.9gr of #9 with a 180gr. XTP. It averaged, almost exactly, 1200fps. It’s not a weak load, but nowhere near where I'd like to be or what the 10mm is capable of. Double UGH. The only thing I can think of now is to make the slide heavier to reduce is speed back and forward – or get a S&W 1006. If there was some way to incrementally add an 1/4 ounce or so, I might be able to figure this out. Maybe real metal, iron sights. (Is that an oxymoron?)

So to compile the previous poster's thoughts with my experience, it seems the G20 is best shot with the factory recoil spring and not-too-hot loads. The magazine spring may help the problem, but it does not solve it, and it causes another problem by locking the slide back with one round remaining in it. The G29 does not seem to be affected as much by the hotter rounds, though as others have said; I have not spent as much time testing it. (The G29 has a double recoil spring - does that matter?)

Taterhead
07-06-2011, 11:29
As I mentioned before, the stock G20 has been 100% even with stout loads (200 @ 1200+ or 180 @ 1335). Only the plus-power recoil spring has yielded any problems for me.

21Carrier
07-06-2011, 12:09
Mountain, that really sucks. I am almost thinking you should send it back to Glock. I've never heard of a G20 that wouldn't tolerate hot loads stock. That would really aggravate me.

Also, maybe you have the old magazine followers or something. I just think there's definitely something wrong.

Mountain10mm
07-06-2011, 12:21
Hey Taterhead, wanna trade 20's?

Ramjet38
07-06-2011, 17:55
Not saying this is your problem, but I would take a look at it and correct if you think even if there's a remote possibility.

Light plastic gun...limp wrist...stovepipe (possible).

http://www.reviewsofthings.com/guns/glock-problems-diagnosing-repairing-fixing.html

Good Luck!

21Carrier
07-06-2011, 18:02
Not saying this is your problem, but I would take a look at it and correct if you think even if there's a remote possibility.

Light plastic gun...limp wrist...stovepipe (possible).

http://www.reviewsofthings.com/guns/glock-problems-diagnosing-repairing-fixing.html

Good Luck!

HAHA! When I clicked on your link (after reading your comment) I expected to see some sort of joke page that looked kind of like the following:

Glock Problems and Solutions:

Gun doesn't work - - - - - - quit limp wristing!

I figured it was gonna be a funny joke, but damn you it was real help!

Ramjet38
07-06-2011, 18:44
HAHA! When I clicked on your link (after reading your comment) I expected to see some sort of joke page that looked kind of like the following:

Glock Problems and Solutions:

Gun doesn't work - - - - - - quit limp wristing!

I figured it was gonna be a funny joke, but damn you it was real help!


:supergrin:
Nobody wants to admit it, and when I had hulls coming back in my face I couldn't figure out what was wrong. Somebody set me straight and no more problems.

Taterhead
07-06-2011, 19:18
Hey Taterhead, wanna trade 20's?


There are many like it, but this one's mine. Thanks for the offer though.