It won't be surprising if the Glock tech inspects the G20, maybe replaces some springs or other parts just to be on the safe side, and then test-fires it with a magazine or two of whatever mainstream factory ammo they're using at the moment. If it feeds and functions normally with their factory ammo of the moment, that will in all likelihood eliminate the gun as the factor responsible for the owner's problem.

That will just leave the ammo and the owner.

 

Gen 3 is the best gen. Never had any problems with mine. Laser accurate too.

 

Slowly acquiring more ammo for a test between the gen 5 g 20 and sig xten. The few rounds I have through both have been fine. A combination of 180 fmj and 200 hardcast and some fast 155. Both guns stock. Interested to see if the 220s work

 

Get the mag springs and not the barrel. At least, not until you try out the mag spring upgrade. Glock will just swap out the parts.

I think the issue is one of timing of the feed cycle, not a problem with the barrel. A heavier recoil spring may slow the rearward phase of a slide cycling but it speeds up the forward portion. I think the fix (if there is one) is a heavier magazine spring much more so than a heavier recoil spring. That being said, I’ve had no trouble between 3 G20’s, but that doesn’t mean the problem doesn’t exist. If I had trouble the first thing I would do is shoot ammo from one of the majors (Federal solid core comes to mind). If the trouble persisted I would use a heavier mag spring before changing recoil springs.

In my Gen3 G20 I use a 19lb recoil spring on an uncaptured guide rod; using a 22-24lb spring does not solve the bolt over round feed problem, it can actually make it worse! with 200 &220 Underwood hard cast the slide is moving too fast for the rounds stacks to move up in the mag. What works is a stronger mag spring. What I have used successfully is a Rowland 460 mag spring for the Glock 21. It reduces the mag capacity of the G20 from 15 to 13 rounds but works 100%!
My gen4G20 works fine with stock mags as well as the SLR mag 5 round mag extensions.

 

Yes, standard Glock G20 mag springs are very weak. I do not run any stock mag springs as I was having the same issue. When you combine the extra powered mag springs and polished chamber and feed ramp I mentioned earlier in the thread, the gun runs amazingly fast with no issues. The higher powered RSA will save your gun from damage with the higher powered loads while the extra strength mag springs will make sure each round is ready to go when it is time.

 

I've looked hard at the 10mm. I always have plenty of 40 around and most 10s handle them with impunity. If I do buy one it'll be a XDM 4.5

 

To be clear, while I have sent the pistol off to Glock and want to give them a chance to address the issue, I really don't expect them to make meaningful changes. My guess is they will put a few rounds of moderate-velocity 180gr FMJ through it and say, "This is fine." (Or: "This is Perfection"©)

Based on the kind of FTF I'm getting (I have a pic now), I'm inclined to believe that the slide is outrunning the magazine spring and the increased-power magazine springs are the right fix. So, yes, for everyone who has suggested that, I'll repeat that I already had those springs on order several days ago.

There does seem to be a pretty consistent pattern with these problems presenting more often in Gen 5's than 3's and 4's. Interesting.

 

Someone once posted which ammunition Glock uses for function testing. Glock tests their 10's with actual macho 10mm as used by mallrats who think they bought a howitzer, if I remember correctly it was Doubletap and Underwood.

 

Update:
Got the pistol back from the factory. Is it possible they changed the optic mount filler plate? I thought the original was plastic, I think the new one is metal. Maybe to add slide weight? Other than that, not sure what they did.

The good:
The extra-power magazine springs definitely make a big difference 👍

The bad:
Any recoil spring configuration that differs much from than the stock/OEM RSA is unreliable, even with the extra-power magazine springs. I only got good reliability with one particular (relatively light) DPM RSA configuration and with the stock/OEM RSA. I believe I still had one malfunction each with each of those, but given the volume of shooting that I was doing without cleaning or re-lubricating, with a pistol that's still getting broken in, perhaps that's to be expected.

I had less than an hour to shoot, and at >$1 per trigger pull, I couldn't be quite as scientific and thorough as I'd like to be. In any case, if I can get through a couple boxes of 200gr hard cast (with no malfunctions) on my next range trip with the stock RSA and extra-power magazine springs, that will be my setup. I wish I could use a heavier RSA, but that doesn't seem to be an option.

 

Glad the mag springs helped. Next step I would do since the RSA's didn't make a difference is to polish the chamber of your barrel to a mirror finish and slightly radius the edges of the chamber. It really helps the 10mm rounds feed into the barrel and eliminates any rough spots. I only have to do this on the 20/40's I own. The nose of the 10mm combined with the feed angle will grab even the smallest imperfection in the chamber and seize like an engine running sand. Running rounds through the barrel will also smooth it out but I hate wasting ammo to get a gun to run right.

 

Hi All,

I've had a few customers contact me about feeding problems with the Gen. 5 G20, also using our guide rod and Wolff springs. Seems the guns don't like the heavy hardcast bullet design. To complicate things, I received a shipment of Wolff spring that were shorter. Always hesitant to mention another vendor, but Wolff claims no issues and springs are correct as recieved. Previously, the spring free length was always approx. 5.25" - but my springs received in one order and sent to a bunch of customers were 4.5", causing lack of in battery pressure.

Let's just say my latest order of Wolf springs are again at 5.25". If anyone bought the spring for me and had this issue, I'll absorb it and give you a free spring replacement.
Thanks, Billy

Jager Products, Inc.

 

Wow, thanks so much for commenting. I'm going to check the length of the springs I bought from you. I will very happily pay you for the longer replacement springs if mine are in fact too short.

 

I'm hearing a lot of complaints about the Gen 5 "Marksman" barrels compared to the previous generation polygonal barrels. My Gen 3 G20 SF has always been 100% reliable with all ammo including 40 S&W ammo and all reloads and full power Underwood, Buffalo Bore, and Double Tap ammo.

I would not buy or recommend a Gen5 Glock 20 to anyone and if I somehow ended up with one, the first thing I'd do is put a KKM barrel in it.

 

While I had carried a 44Mag revolver at times with reloads of 300g hard cast bullets at a choreographed 1377fps, loading a healthy dose of H110 out of an OLD Ruger Vaquero Bisley recoil management was a concern!!!! Better hit it with the first shot cuz waiting for the recovery might take a wee bit too long. I could have shot buffalo with that load.

With more time spent in Montana I looked to what lads in Montana carry in the woods. A lot of 10mms and still some nuclear revolver loads. I decided to go the route of a 10mm for the lighter weight, better mag capacity, and faster recoil recovery for shots on target.

I did some research and noted that a lot of the G20 gen5 offerings were suffering from functioning problems and also stabilization of the 220g bullet weights. I was going to be content with a 200g loading and do some of my own reloading. My G22 gen 4 will shoot my reload of 180g at 1164fps all day without any hiccups. So, my decision was to go with a G20 gen 4 and reload with my recipes. Now a 200 cast coated bullet is hitting 1284 out of a stock G20 gen 4 and I'm still working on some other recipes that might work out better for my needs.

 

Maybe take it back to stock and try your “hotter” loads? My gen 3 G20sf eats everything I feed it including Underwood and BB hard cast hunting rounds.

 

After some additional testing, I've concluded that my Glock 20 Gen 5 isn't sufficiently reliable with any full-power 200 grain loads, despite various attempts at modifying the gun to address the reliability issues.

The extra-power magazine springs helped a lot, but I'm still getting a failure to feed on approximately 1 out of every 20 rounds or so. For a "save my life" tool, that's simply unacceptable.

In addition to the extra power magazine springs, I've tried about a dozen RSA configurations (stock, DPS, Jager Products), and a KKM barrel. No combination of parts yielded the 99%+ reliability that I'd consider adequate. (I also sent the pistol in to Glock for service in case it had some clear mechanical defect in need of repair.)

The rounds I tested:
-Underwood 200 grain hard cast
-Federal 200 grain hard cast
-Grizzly 200 grain FMJ Bear Load

This is all very disappointing, of course. I bought the G20 specifically to shoot the type of loads I mentioned above.

Are there perhaps yet more modifications I could try in order to achieve adequate reliability? Sure, but come on, this ammo is >$1 per trigger pull, and I'm tired of burning through ammo just to fail reliability tests.

The silver lining is that this pistol is 100% with 180 grain loads. If I had to use this pistol for predator defense, it does run Underwood's 180 grain flat-nose FMJ at 1300 FPS. Not an ideal bullet design, but that's a pretty potent load that I think would still yield some good penetration.

Having said that, there really isn't much reason for me to reach for the G20 when I could run my XTen or even my S&W 69 .44 mag.

I hope others find my experience enlightening 👍

 

After some additional testing, I've concluded that my Glock 20 Gen 5 isn't sufficiently reliable with any full-power 200 grain loads, despite various attempts at modifying the gun to address the reliability issues.

The extra-power magazine springs helped a lot, but I'm still getting a failure to feed on approximately 1 out of every 20 rounds or so. For a "save my life" tool, that's simply unacceptable.

In addition to the extra power magazine springs, I've tried about a dozen RSA configurations (stock, DPS, Jager Products), and a KKM barrel. No combination of parts yielded the 99%+ reliability that I'd consider adequate. (I also sent the pistol in to Glock for service in case it had some clear mechanical defect in need of repair.)

The rounds I tested:
-Underwood 200 grain hard cast
-Federal 200 grain hard cast
-Grizzly 200 grain FMJ Bear Load

This is all very disappointing, of course. I bought the G20 specifically to shoot the type of loads I mentioned above.

Out of curiosity how many rounds do you have through this gun total?

 

Couldn't say exactly. Probably more than 500 but fewer than 1000.

(I also sent the pistol in to Glock for service in case it had some clear mechanical defect in need of repair.)

Hopefully, Glock can rectify the issue one way or another.

 

To be clear, the pistol was returned to me prior to my final testing. Whatever is deficient about this gun, Glock wouldn't or couldn't fix it.

 

Or, consider running the major American ammunition factory loads, since that's what Glock uses in their in-house testing?

If they don't test using specialty loads developed by small companies, and any particular G20 runs normally with major manufacturer loads, they may not consider there to be a 'problem' with one of their G20's.

Sure, a small specialty ammo maker may test their loads in-house with a gun made by one or another of the major gun makers, but how much of their loads do they run in their testing, and does that guarantee that each and every other such gun will reliably feed & function with their loads? Do they guarantee functioning?

Trying to 'magnumize' 10's has been a will-o'-the-wisp endeavor for a while.

The last I looked to try and find what the Sirius Patrol was using in their G20's, the best I could find was info from 2018, and reportedly they used 10mm ammunition made by Serbian manufacturer Prvi Partizan, using a jacketed flat-point bullet. The Prvi website info lists a 170gr FPJ at 1115fps, and a 190gr FPJ at about 1050fps, but I didn't see any definitive info about which load the Patrol may be using.

Either way, if the Sirius Patrol considers either of them to be sufficient for their use, would any American feral animals be larger and heavier threats than polar bears?

Having grown up as a Magnum revolver shooter, and having worked at an agency who authorized .44MAG duty revolvers, I can understand the temptation to 'magnumize' the mid-bore 10mm Auto. While 10mm revolvers used by handgun hunters might not be fussy about the ammo they use compared to pistols, feeding & functioning-wise, does that make it possible for all 10mm pistols to feed & function with all 10mm ammo, including the hot specialty loads? That's a question for the 10mm owners, as well as the various makers of new 10mm pistols.

 

Or, consider running the major American ammunition factory loads, since that's what Glock uses in their in-house testing?

If they don't test using specialty loads developed by small companies, and any particular G20 runs normally with major manufacturer loads, they may not consider there to be a 'problem' with one of their G20's.

Sure, a small specialty ammo maker may test their loads in-house with a gun made by one or another of the major gun makers, but how much of their loads do they run in their testing, and does that guarantee that each and every other such gun will reliably feed & function with their loads? Do they guarantee functioning?

Trying to 'magnumize' 10's has been a will-o'-the-wisp endeavor for a while.

The last I looked to try and find what the Sirius Patrol was using in their G20's, the best I could find was info from 2018, and reportedly they used 10mm ammunition made by Serbian manufacturer Prvi Partizan, using a jacketed flat-point bullet. The Prvi website info lists a 170gr FPJ at 1115fps, and a 190gr FPJ at about 1050fps, but I didn't see any definitive info about which load the Patrol may be using.

Either way, if the Sirius Patrol considers either of them to be sufficient for their use, would any American feral animals be larger and heavier threats than polar bears?

Having grown up as a Magnum revolver shooter, and having worked at an agency who authorized .44MAG duty revolvers, I can understand the temptation to 'magnumize' the mid-bore 10mm Auto. While 10mm revolvers used by handgun hunters might not be fussy about the ammo they use compared to pistols, feeding & functioning-wise, does that make it possible for all 10mm pistols to feed & function with all 10mm ammo, including the hot specialty loads? That's a question for the 10mm owners, as well as the various makers of new 10mm pistols.

Dude...🤦‍♂️

1. Every single round through this pistol was a factory load, within SAAMI specs, purchased from a major retailer.

2. As I clearly stated, among the loads I tested was Federal 200 grain hard cast, and this pistol choked on it -- if Federal isn't a "major brand" to you, well, I don't know what to tell you 😂

3. Please recommend other 10mm hard cast loads that you would recommend I try, since apparently I've chosen the "wrong ones," in your opinion. (Even though the ones I chose are the most popular ones out there, with the possible exception of Buffalo Bore, against which you would certainly levy the same complaints as you did against Underwood.)

I will not make or abide excuses for any pistol manufacturer. My Sig XTen runs everything. Lots of guys have Gen 3 and 4 Glock 20s that run everything. My Gen 5 Glock 20 falls short, and it seems like a lot of other people are having similar problems with this particular model.

The problem is the pistol, not the expectations of it that I have.

 

I know some people have different experiences, but a semi auto pistol is a real balancing act between the locking system, recoil spring, slide weight, and magazine spring strength. Asking this ballet to work with everything from 135 grain bullets at 1,600 fps, 220 grain bullets at 1,100 fps and powder puff factory 180 grain loads at 900 fps…to me might be just too much.

My gen 4 20 is pretty good, but the only handgun I’ve found that works super reliably with wildly varying power level loads remains the revolver.

 

Nah, I could be sympathetic to that perspective if that was the way these pistols were advertised -- for example, if a gun manufacturer came out and said, "Our pistols are designed to function reliably only with SAAMI-spec rounds with 180 grain projectiles," then sure, shame on me for expecting reliable function with anything else.

But that's not what actually happens, because such transparency would deter purchasers who (for example) want to run 200 grain loads. Manufacturers want to have their cake and eat it, too: implicit or explicit declarations of broad reliability, and then when their product fails, they can blame the end-user for using the "wrong" ammo, even though that ammunition falls within whatever vague guidance the manufacturer did provide (usually something like "use quality factory ammunition of the correct caliber" or something).

 

Just curious, but do you go by Mark Lives Things on the S&W Forum ( smith-wessonforum.com) ?

 

Yep!

 

I admire your persistence.

 

Haha thanks, I wish it wasn't necessary. I'm going to be trying another M&P 10mm again soon, and I'm fully prepared for another nightmare 😂

 

Just to prove I'm not a Glock hater: I tried another M&P 10mm, hoping that S&W had fixed the magazine drop problem I experienced previously and documented extensively. Nope! Exact same problem. Here's the video:


And here's the post where I've documented this happening to a bunch of other people:

 

Been following your issues....had/have the same issues with my Glock 21 Gen 5......intermittent FTFs.....I have 2 Gen 4 Glocks - a 21 and 30 and they have thousands of rounds with zero failures....something about the Gen 5 is a problem at least in my humble opinion......and my 1911s have combined more than 60,000 rounds with only 4 failures total and two were magazine related so I wonder what it is with the Gen 5s......its unfortunate because my G21.5 shoots wonderful and I really like it but it isn't 100 percent reliable..... after 750 rounds.

 

Same here with my Blue Label G21 Gen 5 . Intermittent jams with 230 grain FMJ using all 3 supplied mags . Same Winchester ammo worked fine in my G30 gen4 . After 500 or so rounds I gave up and traded it .

 

Wonderful. Glock messed up Gen 5 20’s and 21’s.

Get a 20.4 and be done with it.

I hear they found the fix for the M&P 10mm. Chuke on Chuke Outdoors youtube channel mentioned it.

You really shouldn’t be having these issues. Obviously, this means you need a Nighthawk 1911 in 10mm.

 

Anyone try the Sig V crown ammo? Doesn’t that zip out at 1200 Fps +??

 

Only in a Sig.

 

So the guy has a pistol that doesn't work for him - right? This is the same guy who managed to talk endlessly about a M&P 10mm pistol that didn't work for him.
I guess he likes to talk cause I never see any resolution.

Just saying...

 

WTF is this comment? 🤦‍♂️

The whole point of discussing this stuff online is to pursue resolution. I've extensively detailed everything I've done toward that end. And you say I just "like to talk" -- have you read anything here? All the ammo I've burned, all the parts I've swapped, all the time spent with customer service departments/gunsmiths, all the frustrating range trips -- this is my time and money that I've been sacrificing, man. You call that "talk"? Ridiculous.

"Just saying...", indeed 🤦‍♂️

 

I hate to see the issues with the 20 gen 5. I’ve ran multiple weights in my stock 29.5 ranging from 155gr to 200gr in fmj and jhp without the slightest hiccup. Hopefully you’ll get it figured out and restore a little faith/trust in the gun.