Glock Pmag 17 rd failure

[TobyJ]

Hi All,

I tried searching on this, but didn't find exactly what I was looking for.  last night, in a local steel challenge match, I had what I think was a 17rd Pmag failure in my glock 34..  I keep 3 mags loaded for these events, 2 OEM glock 17 rounders, which are pretty much all I actually end up putting in the gun, and one 17 rd pmag as an emergency spare.  Since most stages are usually only 18-24 rounds, I have never used the pmag (other than in practice) until last night.

One one stage, they had 2 mandatory reloads, so I had to use the pmag.  It was filled with 17rds of my go to 147gr load, and on 2nd shot, the gun locked up hard.  I wasn't able to rack the slide even, until I ejected the mag, at which point one round went into battery, and another fell out loose, with the mag.  When I picked the mag up after the stage, the next round in line appeared to be trying to sneak out by going straight up through the feedlips, vs. out the front as per normal.

When I got home, I loaded up the pmag with 17 rds again, and with only slight upward pressure on the nose of the bullet, was able to sort of pop it out, straight up, out of the mag.  I tried the same test with the factory mag, and could not make this happen...not surprising, with the metal reinforcement of the OEM.  I'm thinking that since the Pmag doesn't see much use, the spring is still really tight, and when loaded full, was putting a lot of upwards pressure on the rounds, which caused a round to 'pop out'.  Has anyone else seen this before?  I figure one solution would be to load the mag up, and leave it that way to break the spring in, but I think the better plan is to just stick to OEM mags...I didn't buy the pmag to save money, but rather because it was all the shop I was in had.  

Or maybe there is something else I'm missing?  The gun is basically stock, with the exception of a glockmeister stainless guide rod and 15# ismi spring. Loads are 135-ish pf.  I had maybe 1 or 2 FTE's out of probably 1000 rounds with the stock spring, and this is the first issue with the 15#, but it looks to be pretty clearly a mag issue.

Toby J

[Onepocket]

Stick with Glock oem. The more you change, the  more problems you will have.

[Swanny10]

I have 1000-1500 rounds split between 5 pmags. I've never had a problem. However, I rarely top them off all the way. Do I trust them as much as factory mags? No. Only because they are aftermarket. If you're certain it was a mag issue and money is not a factor then it's a simple fix. 

[Southpaw]

Sounds like it was maybe a double feed?  Which is usually mag related.  And sounds like your feed lips are spreading too much.  Even when new that shouldn't happen.  Magpul has good CS, if you contact them they'll probably send you a replacement mag.

[Rangerdug]

It would say that you have a bad mag; However, to say that is indicative of Magpul is BS. I have put 5,000 plus through mine without issue.
I would call Magpul and let them know, I am sure they would replace it.


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[KommBat]

I guess you have marked your mags....

Keep this one and only use it in Training to practice getting rid of double feed´s.

I wish I had a mag like this for Training!

[Nathanb]

The very first batch of pmags had issues they sent out replacement bodies. It could be one of those

[mreed911]

Brass or steel cased ammo?  I had a problem with steel cased and when I contacted Magpul was told that because there's no metal liner in their mag, steel (Wolf ammo, in my example) had more friction against the sides of the mag body and suggested a little BreakFree in the mag would lube it up and using only brass would be best.  For the difference in money I only go with Glock OEM now.

Edited December 3, 2016 by mreed911

[TobyJ]

Thanks for all the input  it was brass cased reloads that I had the issue with

 I use magpul mags for my 300blk ar, super and subsonic without issue, so I don't think it's a bad product  that said, the metal liner in the factory mag does seem superior.  

picked up 2 factory packaged glock brand mags at the gun show for $20 each, so now I have 4 for primaries. as others said, I'll keep the pmag for practice, and see if I have any other issues with it  

 

TobyJ

[Matt in TN]

What is your OAL of loaded rounds?  I just found my 147gr FMJ load will bind in the Magpul mags, but run fine in the Glock mags.  OAL is 1.168".  It seems the Magpul is very slightly smaller front to back than the Glock, and it acted just like you describe.

I'm going to sand the front interior of the mag body a little and see what happens.

[TobyJ]

My loads are right at 1.160, and my problem seems to be more the mag giving up rounds too easy, vs something hanging up.  

TobyJ

[Gary1911A1]

On 12/2/2016 at 9:48 PM, Nathanb said:

The very first batch of pmags had issues they sent out replacement bodies. It could be one of those

I bet this this is the issue too. Call them and they will make it right.

[Nik Habicht]

On 12/6/2016 at 11:16 AM, TobyJ said:

My loads are right at 1.160, and my problem seems to be more the mag giving up rounds too easy, vs something hanging up.  

TobyJ

That's really long.....

I'm running my reloads 1.06 to 1.07, regardless of projectile weight from 115 gr up to 147 gr.

 

[TobyJ]

14 hours ago, Nik Habicht said:

That's really long.....

I'm running my reloads 1.06 to 1.07, regardless of projectile weight from 115 gr up to 147 gr.

 

What would be the advantage to running this short?  I picked 1.160 based on a combination of the plunk test (this was close to max on my Alpha Wolf barrel with the Xtreme 147) and some different reloading data.  It proved to be accurate and hit my PF target, so I didn't fool with it, and i got the impression that loading as long (close to the rifling) as possible was a good plan.   Am I missing out on something?

Now blue bullets in my alpha wolf have to be loaded that short in order to pass the plunk. On the factory glock barrel, I can go much longer, and usually go about 1.14.

TobyJ

 

[Swanny10]

What specific part of the plunk test are they failing? Won't go in all the way? Won't spin? Won't fall out easily?

[TobyJ]

The blue bullets would drop in, but would not spin, at about 1.10 in the Alpha wolf.  Someone suggested it was just the profile of that bullet, and not to worry too much, as long as it dropped in.  Well, I think that left the bullet right at the rifling, and on one occasion the gun locked up at the 'unload and show clear' command...took a bit of a kung fu chop to get it open. The bullet had a big cut on it, just above the case.  If I load down to like 1.05, they drop, spin, and fire just fine in the Alpha.  And as I said, the factory barrel plunks and spins all the way out to 1.14, which is as long as I've tried.

 

TobyJ

[Onepocket]

On 12/7/2016 at 9:47 PM, Nik Habicht said:

That's really long.....

I'm running my reloads 1.06 to 1.07, regardless of projectile weight from 115 gr up to 147 gr.

 

+1 On what he said. Why load long at all? The plunk test is not the only test the round has to pass. 

[TobyJ]

I'm fairly new to 9mm, and most of my reloading prior has been with 300blk.  There COAL becomes a big deal, as you go from 110 gr super to 220 gr subsonic loads, all the while trying to fit not just mag length, but specific profile dimensions of another cartridge, the 5.56 NATO.  COAL can also make or break function of the gas system / velocity relationship, depending on powder...which also matters more than in many loads.

So when I did my research on 9mm, most guides have the 147 gr projectiles loaded out to around 1.160. Then, I found several threads, on here and other places, where it was suggested that I use a fired case that will tightly hold a bullet, to find the max COAL that my chamber would allow, and back off of that by .015 or so to allow for variation.  This lead me to believe that one of the characteristics of the 9mm was that it liked to be loaded as close to the rifling as possible.

But now you say that long is not always best.  This is why I love learning, and love reloading.  My only other thread on here so far has been about my strange desire to test more powders, even thought TG does all I need...or at least all I think I need.  Likewise, I found a load and a COAL that meets my PF goal and shoots well...but if there is something else to experiment with, which might lead to a better load, I'm all ears...or eyes in this case.

Thanks for all the help!

 

TobyJ