Magpul 21 rd mag failure to feed

[seabiscuit]

I’d been carrying a Magpul 21 rd mag as a spare for my G19.4 and G19X, but after seeing a post (I think it was from JodyH) mentioning failures to feed hollow points from Magpul mags, I decided to try it out.

I racked all 21 147 gr HSTs through my G19.4, and the last round failed to feed. Nasty failure too - had to lock the slide back, push the round back into the mag, then eject the mag.

Now, that only happened with the very last round, so I’d basically be out of ammo anyway, but I’m switching to the OEM 24 rd for my spare now.

Is there any reliable, comfortable baseplate worth trying? OEM baseplates bite - those back corners are sharp. More cant helps, but it could be better.

FWIW, guns wear APLc’s and are carried in a JMCK AIWB rig, and I have AIWB mag carriers from him for 15 and 24 rd mags. I switched to a single PTD loop to adjust cant on the mag carrier.

I can add a picture of the FTF later if it helps.


Sent from my iPhone using Tapatalk

[Caballoflaco]

Manually cycling ammunition is not a way to determine reliable feeding of a magazine in a semi auto pistol. The only way to know for sure if a gun works with a certain magazine and load is live fire. Unfortunately, you just can’t reproduce recoil, slide velocity, consistency of grip and I’m sure a myriad of other factors by manually running the slide.


Also, it’s not considered wise to chamber a round you plan on using for self defense more than a couple of times due mainly to bullet setback that can happen during the loading process.

[Leroy Suggs]

Manually cycling ammunition is not a way to determine reliable feeding of a magazine in a semi auto pistol. The only way to know for sure if a gun works with a certain magazine and load is live fire. Unfortunately, you just can’t reproduce recoil, slide velocity, consistency of grip and I’m sure a myriad of other factors by manually running the slide.


Also, it’s not considered wise to chamber a round you plan on using for self defense more than a couple of times due mainly to bullet setback that can happen during the loading process.

^^^^^^^^^^^^^^^^^^^^^^ This.

[WDR]

I have had failure to feed malfunctions with the Magpul 21 round mags as well, using JHP or flat nosed 147gr FMJ ammo. They seem to run 100% with round nosed ball ammo of all weights. I don't trust them for carry use, but I have a couple for range use, just because they are a nice size.

ETA: This is in actual use, not hand cycling ( which, as mentioned, isn't a good measure of reliability).

[seabiscuit]

Caballo Flaco, makes sense. But if it won’t run reliably manually cycling, I’m not going to trust it actually firing, at least until I get to the range.

Have you witnessed bullet setback? Every day, I must unload and reload my pistol. So the top two rounds get chambered quite a bit. Every time I go to the range, I make sure to fire these rounds, and I’ve never had an issue.


Sent from my iPhone using Tapatalk

[Kyle Reese]

Caballo Flaco, makes sense. But if it won’t run reliably manually cycling, I’m not going to trust it actually firing, at least until I get to the range.

Have you witnessed bullet setback? Every day, I must unload and reload my pistol. So the top two rounds get chambered quite a bit. Every time I go to the range, I make sure to fire these rounds, and I’ve never had an issue.


Sent from my iPhone using TapatalkOEM 24s don't seem to exhibit any of the shortcomings of the MagPul 21s. Also, I'll echo the sentiments of the posters in this thread that have pointed out that manually cycling your ammo isn't really a valid metric to determine the reliability of your 21s. My 21s don't like steel cased ammunition at all, but I came to this conclusion during live fire.

Regarding clambering the same round over and over, I'd recommend against the practice. For me, any defensive handgun cartridge is relegated to the range bag after being chambered more than twice. For carbines, it's after a single chambering.

Check out Doc GKRs take on this topic.

https://r.tapatalk.com/shareLink/topic?url=https%3A%2F%2Fpistol-forum%2Ecom%2Fshowthread%2Ephp%3Ft%3D3002&share_tid=3002&share_fid=18787&share_type=t&link_source=app

duty ammo failure from rechambering


Sent from my VS995 using Tapatalk

[BK14]

Caballo Flaco, makes sense. But if it won’t run reliably manually cycling, I’m not going to trust it actually firing, at least until I get to the range.

Have you witnessed bullet setback? Every day, I must unload and reload my pistol. So the top two rounds get chambered quite a bit. Every time I go to the range, I make sure to fire these rounds, and I’ve never had an issue.


Sent from my iPhone using Tapatalk


Granted manually cycling doesn’t replicate firing, but I’ve had enough failures with magpul mags to not trust them. So regardless of why you got to this conclusion, I’m glad you did. The 24 rounders are awesome.

If the oem baseplate is an issue, try rounding out the back corners of the mag. You can also try older generation baseplates, vickers, or 10-8, but I think with some sand paper you could probably make them work.


I un-chamber my duty gun a few times a week. After I chamber the round a couple times, as long as there’s no setback, I just cycle it lower into the mag and pull up some new rounds. Obviously if it’s set back it gets chucked.

[seabiscuit]

I’ll double check my top rounds for setback and maybe put them deeper in the mag. They do get discolored and I make sure to shoot them at my first opportunity but I’ve never had an issue.


Sent from my iPhone using Tapatalk

[Chance]

I can add a picture of the FTF later if it helps.

Known issue: read this (https://pistol-forum.com/showthread.php?28488-Current-Groupthink-Magpul-Glock-Magazines&p=673383&viewfull=1#post673383). I only use OEM mags at this point.

[noguns]

I use them for range use only.

I only use OEM for carry.

[Caballoflaco]

Have you witnessed bullet setback? Every day, I must unload and reload my pistol. So the top two rounds get chambered quite a bit. Every time I go to the range, I make sure to fire these rounds, and I’ve never had an issue.


Sent from my iPhone using Tapatalk

I’ve seen bullet set back in 9mm glocks with 124gr gold dots in as few as 4-5 loadings/unloadings. It was minimal and the rounds still fired, but I don’t load/ unload a round more than 3 times if it’s for carry.

[ST911]

I've had good luck with a bunch of pmag 21s. Good thread on the topic here: https://pistol-forum.com/showthread.php?24187-Magpul-Glock-PMag-21

On bullet setback, something I posted elsewhere recently:


Make a tick mark on the case head with a sharpie each time it's chambered. When you have 2-4 marks, rotate it out.
Rotate when there is any deformation to the rim or case mouth.

Check this out from Claude Werner: https://www.facebook.com/ATLFirearms/photos/i-was-asked-about-the-system-i-use-to-make-sure-duty-ammunition-doesnt-get-chamb/1357565304317577/

Setback is real but varies wildly, even with a manufacturer and particular sku. Crimp, jacket composition, sealants and adhesives, grooves and cannelures, slide energy, bullet profile, case taper, etc. During deliberate experimentation some major duty/carry rounds were chambered 2-3 dozen times with no effect, and were fired, extracted, and ejected without issue. Some show setback at 2-3x. I worried about a couple of 357SIG rounds when chambering them the first time.

Setback may have serious or negligible effect on pressures, depending.

It's just not worth it. Don't download at all or as often, or buy a few extra boxes of carry ammo.

[seabiscuit]

Good idea re: the sharpie tick mark


Sent from my iPhone using Tapatalk

[HeavyDuty]

I only use my Magpul 21 rounder as a barney, but it’s been trouble free.

[NETim]

My MagPul 21's have been 100% with 124 grain RN coated lead reloads. But I only game with them. I have not tried to run any other ammo through them.

[echo5charlie]

Caballo Flaco, makes sense. But if it won’t run reliably manually cycling, I’m not going to trust it actually firing, at least until I get to the range.

Have you witnessed bullet setback? Every day, I must unload and reload my pistol. So the top two rounds get chambered quite a bit. Every time I go to the range, I make sure to fire these rounds, and I’ve never had an issue.


Sent from my iPhone using Tapatalk

Hand cycling is a Fudd move. Avoid it. OEM mags can fail this "test" in both directions.

[msstate56]

After having used Magpul Glock mags of all sizes since they were released, I’ve come to the conclusion they are range mags only. I’ve had enough issues with them to no longer trust them. I’ll continue to use them in training only, but I will only buy factory mags from here forward.

[pastaslinger]

Is there any reliable, comfortable baseplate worth trying? OEM baseplates bite - those back corners are sharp. More cant helps, but it could be better.

Arredondo

[Wake27]

Arredondo

First class I ever went to, one of the shooters had these and they just kept exploding. Reviews online seem to indicate it wasn’t an isolated issue.


Sent from my iPhone using Tapatalk

[pastaslinger]

First class I ever went to, one of the shooters had these and they just kept exploding. Reviews online seem to indicate it wasn’t an isolated issue.


Sent from my iPhone using Tapatalk

I've had good experience with them and other people have as well
Not sure why this particular person had issues. The way that the basepads fits together makes me wonder if they broke the tabs or something.