40 S&W and Glocks

[KevH]

It seems to get asked every other week on every gun forum so here is a short explanation of 40 S&W Glocks:

I've been a Glock armorer at a medium sized police department for 12 years and carried a G22 for a chunk of that time. I've run the gambit with Gen2 and Gen3 G22's. There are two main issues.

With the Gen2 G22's Glock essentially took a 9mm G17 frame and slide and bored it out to 40 S&W. They didn't account for higher pressure and didn't put enough case support in the chamber of the barrel and if you ran extra hot ammo OR you had ignition without the gun being completely in battery (which was extra likely with a G22 because the recoil spring would wear out faster due to the higher pressure ammo) you would blow up the case and possibly the gun in the process.

Glock began to correct these issues in the late Gen2 guns and early Gen3 guns. They changed the chamber specs and added an extra pin in the locking block of the frame. Some people will tell you the extra pin was superfluous. On 40 S&W Glocks I see that metal pin break fairly often. So, I can tell you that there is extra stress going on in that area of the gun and here is why…

In Gen2 and Gen3 guns the 9mm and 40 S&W use the same recoil spring assembly (RSA). Weird huh? Sig and most other brands have a different spring between those two calibers. Not Glock. The 40 S&W guns wear out RSA’s faster pure and simple. As the RSA wears out the plastic frame of the 40 S&W guns really begin to absorb a fair amount of recoil. That flexing ends up placing stress on the locking block and breaks the pin. But wait, there’s more…

When WML’s came out most were plastic. I remember around 2000/2001 when the Gen3 guns were arriving and every cop went out and bought a M3 light and a pouch for it on their belt and would draw their gun and stick it on and think they were cool (some things only look truly stupid in retrospect). Those plastic lights like the M3 and the Glock light didn’t fit super tight and their plastic bodies allowed some flex during recoil. Enter the X200 and TLR 2005ish.

Some guys started seeing feeding issues with the M3 light. When the X200 and TLR came out some really big feeding issues started to show up. What was happening is the metal light was rigid on the dustcover of the frame and wouldn’t allow it to flex. On a TLR where the light mount tightens, the issue was even more pronounced. So if a guy ran a metal light on a brand new G22 he was cool for about the first 1200 rounds or so. Then the issue started to pop up.

Few things going on:
1) No flex in the frame meant the RSA took all the recoil wearing it out faster.

2) Worn out RSA meant most hot duty ammo (like Federal HST) would cycle the gun, but practice ammo would not. Why? The higher velocity ammo would cycle the slide fast enough to function, but would beat the gun to death evidenced by peeing and a broken locking block pin.

3) The Gen3 magazines would also flex around more during recoil and the rounds would tip up in the magazine. So the slide isn’t going at the right speed and the rounds are being presented almost vertical. You end up with a classic failure to feed.


There was a lot of back and forth and denial between Glock and the LE community a lot more shenanigans and then some of us on both sides figured it out. I loved the guys that would run the light until the gun started to FTF and then take the light off and declare everything fine. Little did they know the RSA was now toast and the gun would run because the frame was taking the impact and the gun was beating itself to death. All those guys ended up with broken locking block pins and other issues. Same with the guys that said, “I’ll just shoot duty ammo because that seems to work.” Same deal.

Glock went through several new magazine followers and springs before they finally introduced the Gen4 guns with a new magazine design. They look very similar, but even the first Gen4 G22 mags that came out got it right. But magazines alone don’t solve the problem. So here is what you have to do…

If you want to carry a Gen3 G22 with a light here is the solution:
-Change your RSA every 2500 rounds or so
-Use the latest Gen4 Glock magazines. When mags start to go south dump them for new ones.
-Check the locking block pin once a year to make sure it’s still intact

It is really that simple. I have well over 30 guns in service that couldn’t get through one mag without at least three FTF’s that run flawlessly with that prescription.

Glocks in 9mm and 45 ACP don’t suffer the same issues because the pressure of the rounds is so much less (and different) than the 40 S&W. My department only issues the 9mm round in +P (duty and practice) and I can tell you it won’t wear out the gun anywhere near the way 40 S&W does. I still change the RSA’s on my own 9mm and 45 ACP guns fairly often though. They’re dirt cheap and extra insurance that everything will keep rolling.

I’ve seen a few G21’s that started to develop FTF issues. Simply changing out springs, both RSA and mags, has always solved the issue. Remember, gun springs are like the oil filter on your car. They aren’t meant to last the life of the car or gun and need to get swapped fairly frequently.

[Jeep]

It seems to get asked every other week on every gun forum so here is a short explanation of 40 S&W Glocks:

I've been a Glock armorer at a medium sized police department for 12 years and carried a G22 for a chunk of that time. I've run the gambit with Gen2 and Gen3 G22's. There are two main issues.

With the Gen2 G22's Glock essentially took a 9mm G17 frame and slide and bored it out to 40 S&W. They didn't account for higher pressure and didn't put enough case support in the chamber of the barrel and if you ran extra hot ammo OR you had ignition without the gun being completely in battery (which was extra likely with a G22 because the recoil spring would wear out faster due to the higher pressure ammo) you would blow up the case and possibly the gun in the process.

Glock began to correct these issues in the late Gen2 guns and early Gen3 guns. They changed the chamber specs and added an extra pin in the locking block of the frame. Some people will tell you the extra pin was superfluous. On 40 S&W Glocks I see that metal pin break fairly often. So, I can tell you that there is extra stress going on in that area of the gun and here is why…

In Gen2 and Gen3 guns the 9mm and 40 S&W use the same recoil spring assembly (RSA). Weird huh? Sig and most other brands have a different spring between those two calibers. Not Glock. The 40 S&W guns wear out RSA’s faster pure and simple. As the RSA wears out the plastic frame of the 40 S&W guns really begin to absorb a fair amount of recoil. That flexing ends up placing stress on the locking block and breaks the pin. But wait, there’s more…

When WML’s came out most were plastic. I remember around 2000/2001 when the Gen3 guns were arriving and every cop went out and bought a M3 light and a pouch for it on their belt and would draw their gun and stick it on and think they were cool (some things only look truly stupid in retrospect). Those plastic lights like the M3 and the Glock light didn’t fit super tight and their plastic bodies allowed some flex during recoil. Enter the X200 and TLR 2005ish.

Some guys started seeing feeding issues with the M3 light. When the X200 and TLR came out some really big feeding issues started to show up. What was happening is the metal light was rigid on the dustcover of the frame and wouldn’t allow it to flex. On a TLR where the light mount tightens, the issue was even more pronounced. So if a guy ran a metal light on a brand new G22 he was cool for about the first 1200 rounds or so. Then the issue started to pop up.

Few things going on:
1) No flex in the frame meant the RSA took all the recoil wearing it out faster.

2) Worn out RSA meant most hot duty ammo (like Federal HST) would cycle the gun, but practice ammo would not. Why? The higher velocity ammo would cycle the slide fast enough to function, but would beat the gun to death evidenced by peeing and a broken locking block pin.

3) The Gen3 magazines would also flex around more during recoil and the rounds would tip up in the magazine. So the slide isn’t going at the right speed and the rounds are being presented almost vertical. You end up with a classic failure to feed.


There was a lot of back and forth and denial between Glock and the LE community a lot more shenanigans and then some of us on both sides figured it out. I loved the guys that would run the light until the gun started to FTF and then take the light off and declare everything fine. Little did they know the RSA was now toast and the gun would run because the frame was taking the impact and the gun was beating itself to death. All those guys ended up with broken locking block pins and other issues. Same with the guys that said, “I’ll just shoot duty ammo because that seems to work.” Same deal.

Glock went through several new magazine followers and springs before they finally introduced the Gen4 guns with a new magazine design. They look very similar, but even the first Gen4 G22 mags that came out got it right. But magazines alone don’t solve the problem. So here is what you have to do…

If you want to carry a Gen3 G22 with a light here is the solution:
-Change your RSA every 2500 rounds or so
-Use the latest Gen4 Glock magazines. When mags start to go south dump them for new ones.
-Check the locking block pin once a year to make sure it’s still intact

It is really that simple. I have well over 30 guns in service that couldn’t get through one mag without at least three FTF’s that run flawlessly with that prescription.

Glocks in 9mm and 45 ACP don’t suffer the same issues because the pressure of the rounds is so much less (and different) than the 40 S&W. My department only issues the 9mm round in +P (duty and practice) and I can tell you it won’t wear out the gun anywhere near the way 40 S&W does. I still change the RSA’s on my own 9mm and 45 ACP guns fairly often though. They’re dirt cheap and extra insurance that everything will keep rolling.

I’ve seen a few G21’s that started to develop FTF issues. Simply changing out springs, both RSA and mags, has always solved the issue. Remember, gun springs are like the oil filter on your car. They aren’t meant to last the life of the car or gun and need to get swapped fairly frequently.

Thanks for the extended explanation!

[Chuck Haggard]

It actually is in no way that simple. Seriously.

Your post is the pre 2005 H series G22 solution, and it normally works, most of the time. The problems with the newer guns made since then are rather more epic.

More later when I have time.

[Erick Gelhaus]

We issued the Glock 22, from 1997 until this year. We began replacing Gen 3 versions in '11 with Gen 4s. Prior to the last budget crisis that hit all of us, I had about 300 full & part time cops. We allow other, personally purchased guns but I can truthfully say I had well over 200 Glock 22s in service most of the time. Up to an armorer re-cert in '07, we never heard any recommended round count based parts replacement from the factory.

We first encountered the Gen 3 / WML issue back in 2000 (btw, Business Week devoted the better part of an issue to Glock and this problem back '10). We followed their recommendation of replacing magazine springs - and it mostly went away. Back then though I could count the number of WMLs that were on the round on one hand. Also, back then, we only had two rounds to deal with - 180gr JHP for duty and 180gr TC load for training.

Fast forward to '10. I was watching these issues all over the country and was so thankful I wasnt dealing with them. We had to track three loads - frangible, TC training and a duty JHP. We also also at least 70 Gen 3 22s with WML on them. In Dec '10, we had a K9 handle who shot some training (or tried to) on an outdoor range with duty ammo. The gun did not work, would not run. The instructors on that range had him change to training ammo - it ran; swapped slides & frames, light on or off; all sorts of inconsistencies.

I took the gun, light, training and duty rounds plus a camera to the range the next day. Significant malfunctions with duty ammo (180gr JHP). Hmmm.

We told everyone with a WML on their G22 to come to an outdoor range to test with duty loads. Out of 70, I had 36, 37 that failed to function with duty loads & WMLs. This was primarily failures to feed, mostly what I can only describe as an internal stove pipe during the feed step. Everything was photographed. We also chrono'd our ammo (from memory now), frangible was high 11 or low 12something, 180gr TC was 1055-1060, duty 180gr JHP was 1010. The guns had been running fine with frang & training ammo. We contacted Glock & the duty ammo manf at SHOT. Glock sent out parts to remediate a significant number of the failed guns. When we re-tested with Glock present, using a protocol vetted by other L/E and a couple mil, using duty ammo, we had a 25% failure rate. This included new RSAs and magazines with #9 followers and #2 bodies.

Muzzle velocity has something to do with it, look at the numbers above. The method for attaching the WML had nothing to do with it - that I could hang my hat on. We considered changing duty rounds but they did not have issues in other non-Glock .40cal pistols. Also, what if the company changed the new round or stopped making it. The protocol included fairly loose hand/wrist shooting positions, these were not an issue.

We replaced our Gen 3s in a rather wide serial number range (H through M) with Gen 4s. Late last year and into this, we experienced enough issues with the Gen 4 22s that we are now switching to Gen 4 -17s. I now have 150ish Gen 4 -17s in service and I have more coming to replace the remaining G & older serial number Gen 3s.

Hope this helps.

[BJJ]

I am very interested in this conversation. Please keep it going.

[DocGKR]

I know Angus and his agency's problems--listen to what he has to say, as it is right on target so to speak.

[JHC]

Angus concluded the method of attaching the WML wasn't a factor - but do I understand correctly that the WML is the big FAIL?

Is the prevailing theory still that the WML has some effect on the frame of a .40 (either rigidity or just total mass or something) that leads to slide velocity increasing faster than the system can keep ejecting and feeding more rounds?

[Chuck Haggard]

I tried every single light on the market, including Glock's suggested Glock light, all of them caused our guns to choke a LOT. The light hanging off of the dust cover does two things, it takes flex out of the dust cover and adds weight to the frame, both of which add slide velocity to a system that was on the ragged edge of reliability to begin with.

[JHC]

I tried every single light on the market, including Glock's suggested Glock light, all of them caused out guns to choke a LOT. The light hanging off of the dust cover does two things, it takes flex out of the dust cover and adds weight to the frame, both of which add slide velocity to a system that was on the ragged edge of reliability to begin with.

And the Gen 4 RSA was an approach to retard some of that slide velocity but apparently does not uniformly eliminate the problem.

They needed that .45GAP upper on the standard size lower frame you experimented with.

[rsa-otc]

I do not personally have experience with this problem not being a Glock shooter and only recently started shooting 40 S&W. I do though wish to throw the following observations out there:

From Angus's post 180 grain TC ammo running at 1060sh fps never gave them a lick of trouble but 180 grain Duty ammo running at 1010 fps uniformly caused malfunctions. While I wouldn't think 50sh fps difference would cause any issues, I would think the slide velocity on the training ammo would be greater so wouldn't the training ammo be problematic if slide velocity causing frame flex issues was the culprit. Now I understand that different ammo using different powders can have differing recoil impulses which is why competition shooters are particular about their powders looking for that soft shooting load while maintaining the same velocity and power factor.

After my recent issues reloading for 40 S&W where I found that bullet profile gave me feeding issues depending on the seated depth of the slug/bullet, I am wondering if that is the issue and the reason new RSA's don't completely eradicate the problem. I have never had such difficulty when loading 45 acp or 9mm, it seems to me that 40 S&W is more sensitive to COL. Could the training ammo Angus's department used have a differing bullet profile or seated depth as compared to his duty ammo? Since the frame of the gun is flexing differently when a WML is attached could it be causing the bullet to be presented to the chamber at a problematic angle for said Duty Ammo?

Just my thoughts, I know smarter folks than I have been studying this issue for years.