Interesting Glock Magazine Follower Issue With G31 .357 SIG Magazine

[JonInWA]

This weekend, I'll be shooting my Gen4 G22 with the Glock .357 SIG barrel in an IDPA match-I have some .357 SIG ball that was begging to be used, and I'm moving into a Glock phase for IDPA and GSSF. When preloading my magazines for the match, one of the followers did not pop over the internal feed lip ledge to go into its final position when the last round was expended.

The magazine in question is a G31 .357 SIG specific one, probably 2 years old at the most, and barely used. I have two others; they're probably unnecessary, as in the full-size Glocks the .40 magazines do quite nicely with .357 SIG cartridges, but I decided for basic .357 SIG use I'd get and use .357 SIG magazines. The remaining 2 magazines had no issues with the follower positioning.

Thinking I had a defective spring, I disassembled the magazine, brushed out the tube, and checked the follower for molding burrs or remaining molding sprue, everything seemed just fine.

Then when I placed the spring in the tube checking for fit to further isolate the problem, I noticed that it would click into final position, with a perceptible "click." After that seemed to be working, after exercising it several times, I reassembled the magazine, and experimented with cartridges-it now works fine.

I have no idea what caused the follower hesitation/lag, but evidently the disassembly and working it several times evidently caused it to work itself into compliance (not grunge or residue came out of the tube when I brushed it out).

I'll see how it does in the match; while it's moved from the "naughty" list, it's still in the "trust but verify" category before being used for carry. The follower in question is marked ".357 5"

I've shot Glocks for many years and have multiple and current Armorer certifications, but this problem was a first. Anyone else experience anything similar?

Best, Jon

[Spartan1980]

This weekend, I'll be shooting my Gen4 G22 with the Glock .357 SIG barrel in an IDPA match-I have some .357 SIG ball that was begging to be used, and I'm moving into a Glock phase for IDPA and GSSF. When preloading my magazines for the match, one of the followers did not pop over the internal feed lip ledge to go into its final position when the last round was expended.

The magazine in question is a G31 .357 SIG specific one, probably 2 years old at the most, and barely used. I have two others; they're probably unnecessary, as in the full-size Glocks the .40 magazines do quite nicely with .357 SIG cartridges, but I decided for basic .357 SIG use I'd get and use .357 SIG magazines. The remaining 2 magazines had no issues with the follower positioning.

Thinking I had a defective spring, I disassembled the magazine, brushed out the tube, and checked the follower for molding burrs or remaining molding sprue, everything seemed just fine.

Then when I placed the spring in the tube checking for fit to further isolate the problem, I noticed that it would click into final position, with a perceptible "click." After that seemed to be working, after exercising it several times, I reassembled the magazine, and experimented with cartridges-it now works fine.

I have no idea what caused the follower hesitation/lag, but evidently the disassembly and working it several times evidently caused it to work itself into compliance (not grunge or residue came out of the tube when I brushed it out).

I'll see how it does in the match; while it's moved from the "naughty" list, it's still in the "trust but verify" category before being used for carry. The follower in question is marked ".357 5"

I've shot Glocks for many years and have multiple and current Armorer certifications, but this problem was a first. Anyone else experience anything similar?

Best, Jon

Tagging in. I just picked up a 31.4 last week for a secondary carry gun.

ETA: My mag bodies are marked 4363-03 at the bottom and .357 at the top. Followers are marked .357. Are yours different?

[JonInWA]

Tagging in. I just picked up a 31.4 last week for a secondary carry gun.

ETA: My mag bodies are marked 4363-03 at the bottom and .357 at the top. Followers are marked .357. Are yours different?

My magazine spine codes (at the bottom of the magazine back, underneath the Glock logo) are all 4363-05; followers are marked ".357" on the left top rear follower chute ledge, with "5" on the hold-open ledge. The current posted Glock Armorers Parts List shows this to be the current one.

https://us.glock.com/en/Downloadable-Materials

I'm thinking mine just needed some exercise to work in due to minor tolerance fit; there's a distinct possibility that I may not have ever loaded up, let alone actually used the magazine in question before yesterday. It might have worked itself in on its own, but after manually loading and unloading several time and seeing the follower not coming fully up, I'm glad I worked through the problem (hopefully).

We'll see how it does in actual use; it'll be my first magazine for each stage at the match, so there's a good likelihood things will go to slidelock, fully exercising the magazine.

Best, Jon

[JonInWA]

Whew-the magazine ran just fine with no issues whatsoever during the IDPA match. I utilized it as the initial magazine for each stage, so it was thoroughly used throughout. Apparently the follower just needed a bit of working through before use. Odd problem, but I'm glad the kinks worked themselves out-particularly since Washington is now a capacity limited state, and the magazine is literally irreplaceable to me now.

Best, Jon

[Moonshot]

I'm not sure if my issue is the same as yours, and for me it's 9mm, but it sounds similar.

I have about a dozen G26 and G17 gen 5 magazines, all with the #7 follower (some black, some orange). When holding an empty magazine in one hand and pressing the follower down with the thumb of the other hand and slowly releasing, there is a definite hesitation for the follower to come all the way up along with a pronounce "click".

When loaded for training they have all worked flawlessly.

As a contrast, I have many G26, G19 and G18 magazines - gen 3 and gen 4, and they do not exhibit this. These magazines all have #5 or #6 followers. Some magazines are old but unused, some are new and unused, some are heavily used trainers. None produce the hesitation or the click.

I tried swapping springs and followers between known "good" mags and the ones that are questionable. Placing gen 3 or gen 4 springs and/or followers in gen 5 tubes - I still get the click and the hesitation.

If I place a gen 5 spring and #7 follower in a gen 3 or 4 tube, no issues.

This tells me it's the tube and it's got to be in the top 1/2" of follower travel, but I cannot see or feel anything that might be causing it. If it's dimensional it's slight.

Again, no reliability issues in use, but I wonder if a somewhat weakened spring might fail to feed the last round (or rounds) sooner than I might expect to see a spring needing replacement. Until I hear otherwise, my gen 5 magazines are only for training.

[JonInWA]

It's an interesting hiccup. It was evident, and experienced only with one of my three recent production (2022+) full-size .357 SIG magazines. Before I disassembled the magazine, the follower would only rise to about 1/4" of the top of the tube-not high enough to engage the hold-open latch. It possibly might have been high enough to facilitate chambering the last cartridge, but I didn't test that.

Magazine spring tensility was fine when I disassembled the magazine. After I manually worked through the follower to its final position in the tube, everything was ducky. And I examined and brushed out the tube and follower before reassembling. After reassembly, and in actual repeated use in the match the magazine was fine. My only tentative conclusion is that the magazine needed to be disassembled and the parts then worked through compression and final positioning several times.

After match. the magazine was examined and lightly cleaned; no aberrations were noticed or experienced. I feel comfortable incorporating it into the duty rotation.

Otherwise, the use of Gen5 magazines is crucial in my mind, particularly regarding the 10 round magazines and JHP duty/self defense cartridges, especially 147 gr in my experience. And particularly in the case of a G19; my Gen3 G17 worked just fine with both the Gen5 magazines and concurrently produced non-Gen5 magazines/followers, so there might well be a slide velocity and reciprocation timing issue with the G19. The earlier followers simply do not play well with the 147 grainers, although they seem to work adequately with 115gr and 124 gr JHPs. So for use of 10 round magazines in my G19, the Gen5 10 rounders are the default magazine of choice.

Best, Jon