Tuesday, November 10, 2009

I am become Death, the Destroyer of Gear.

Over the years, I have broken a lot of AR magazines in a lot of exotic ways. At the Appleseed shoot, I broke my very first Magpul P-Mag, and broke it in a suitably bizarro fashion.

As we were preparing to fire our first string from standing, I slapped the mag home in a brisk fashion. Perhaps too brisk. As I went to tug on it to make sure it was seated, my hand reported to my brain that maybe a little less magazine was protruding from the weapon than is usual. I finished tugging and went to hit the bolt release and it wouldn't budge. Ripping the charging handle got no results and so I rolled the carbine to port and gazed stupidly into the receiver and the problem was immediately apparent: Apparently I had slapped the magazine past the catch somehow.

After the malf had been safely cleared, I looked at the mag, and as best I can tell what happened was as follows: When I went to smack the magazine home, my trigger finger was apparently partially depressing the mag release. The nubbin of the catch that was left protruding into the well combined with my vigorous slap on the mag to shear part of the tab on the mag away, allowing the magazine to override the catch and bind the bolt.

Okay. The first step was to fling the magazine back from the firing line, rather than dropping it at my feet, where it might get mixed up with the others. The next prep period, I marked the magazine. Now the P-Mag presented me with another problem: Normally I would stomp or hammer a magazine flat before throwing it away so somebody won't get themselves killed trying to save a few bucks by fishing a busted magazine out of a range trashcan. Absent tools which I didn't have ready to hand, like maybe a hammer and chisel or a gas axe, that wasn't going to happen on this day. So I marked it very distinctively and packed it home.

I guess I'll keep it for a souvenir. Far away from my other mags.

Gun School: The place to go to break gear.


Kristophr said...

Send it to PMAG with a description of the malf.

Either they'll mail a replacement, or maybe even redesign the mags.

Anonymous said...

Hold on.

I'm wholly ignorant of Mag design, but it seems to me that just from the POV of good engineering that the only thing that stops the magazine from being jammed up in the rifle is a little whatsit ( < notice technical term) seems dumb.

I'd have expected a relatively beefy shoulder of some sort that would seat the mag ( to prevent 250lb of adrenaline driven muscular soldier from ramming that magazine into next week) and less beefy but positive release mechnaism to let it go.

Anonymous said...

Bah, some destroyer you are. Maybe if you work on it.

Talk to me when you break a gun in half.

Shootin' Buddy

Anonymous said...

Send it to Magpul.

Anonymous said...

Wow. Did you actually break the PMAG? The pictures don't show the damage all that well.

I don't see how this can be considered a fault with the PMAG at all. Any straight-walled mag would do the same thing.

Simple fix: Don't push the button when you're feeding the magwell :^)

Love it or hate it, the AR is a simple to execute design with a reasonably simple indexed slot and an easily replaceable catch.

A shoulder on a magazine is a fickle thing to index on a magwell that protrudes into harm's way.
That geometry can change quickly, leaving us with a CETME-like personal relationship between magazines that fit right, and magazines that don't work at all.

Triton said...

Zombie snack!

Kristophr said...

Anon: CETME magazines work fine in CETMEs.

When you try to use unaltered H und K mags in a CETME, you start having issues.

ChrisTheEngineer said...

I assume that before you flatten a defective mag, that you remove the spring & follower for spares?

Ed Foster said...

I am so damned jealous! I ran PMags through 6,000 round torture tests up at Smith & Wesson and never had that happen.

Why didn't I have it happen? Because I didn't think about it. I missed it. My nice G.I. familiarity had me doing it Same-O Same-O. Dang.

I owe you one. Next time I'll do better. I wonder if I hit it with a hammer after a St. Bernard whizzes on it....

Will said...

Ed, make that a Malamute(?) or wolf mix. Those dogs kill grass and damage concrete with their urine. Aluminium, also. Don't pen them within range of a heat pump/AC cooler. Gets expensive!

Don M said...

No, you don't remove the spring and follower for spares. If you have a problem, you don't want to move the problem to another mag. The Air Force during WWII borrowed some parts from a crashed aircraft, and every aircraft that the parts went into crashed, including an aircraft that got a wooden arm rest (back before ejection seats). After that, NEVER would the crashed parts be used on a flying aircraft. Ok for labwork, or stinger birds in front of the post office.

pdb said...

+3 to send it to Magpul, not only to get some satisfaction from their customer service, but so they can learn from their mistakes.

IIRC, there was an early batch of Pmags where the plastic formulation was off and they were cracking feedlips.

Caleb said...

I'd like to applaud your choice of the magpul 20 round mag. It is retro cool and approved by the Ghost of John Wayne.

Tam said...

It's also good for those days when you're going to spend about a third of your waking hours in the prone position.

Will said...

I've always thought that the 30 round mags were designed to facilitate "spray and pray". Which leads to Bad Results.

wv= reali... ty. Yep, sure is.

2nd wv= invis... able. Not prone

with a 30, you're not.

Crucis said...

Perhaps this says something about non-metal mags. I've bought all mine used at gun shows by GI suppliers. While I may not shoot as much as some, I've never had one fail. They may be worn and scruffy lookin' but they seat and feed just fine.

Tam said...

"Perhaps this says something about non-metal mags."

It took me a long time to come 'round to trusting P-Mags. Finally, between Pat Rogers praising them and Magpul's own corporate rep for not making junk, I took the plunge.

I have been using and abusing P-Mags for coming up on five years now and this is the first one I've had fail to perform satisfactorily in any fashion.

You could cast a Chevy Cosworth Vega engine block out of the GI-contract STANAG mags I've destroyed over the years, and they're the only other kind of mags I'll use.

Other plastic mags are, in my opinion and experience, utter crap, with the possible exception of the new Tango Down units; I have not personally used the latter, but again, they are spoken highly of by people who have put them through the wringer and who I know aren't just internet blowhards.

Dr. StrangeGun said...

Destroying bad P-mags on-scene? No need for a hammer/chisel/gas tools.

Take your cigarette lighter out and heat one of the feed lips until it droops enough to keep it out of a magwell. If you're lucky it catches fire and you can let 'er sizzle for a bit and deform some more before tossing :)

Conversely, have you measured the width of the magwell in this particular carbine versus others?

Anonymous said...

I'm still unclear on what part of the mag failed. Agree that sending it to Magpul would be your best bet.

"I've never had one fail - yet". There, fixed it for you. :) Usually the metal mags fail in small ways - the occasional double feed. That's why we track malfs and (at least for me) when a magazine has malf #2, it's toast.

Al T.

Tam said...

I'd say 90% of my failures with GI mags have been related to the feed lips, where either a stress crack or just age-related stress and wear lead to the dreaded "volcano". Most of the rest have been from dropping a partially loaded magazine that proceeded to do a Saturn V impersonation, rising to the heavens on a glittering column of brass and suddenly-freed mag spring.

Tam said...

Edited To Add:

For the above reason (Failure Type No.1), I'm a lot more comfortable keeping a P-Mag loaded for long periods of time than a GI unit.

"I'm still unclear on what part of the mag failed."

In the upper (blurry) photo, you can kinda see where the locking tab has had a bevel sheared off the shoulder.

Anonymous said...

Ah - got it. :) You need to quit doing those kettlebell drills or you'll be bending S&W cylinder cranes. :D

Al T.

Tam said...

Says a poster at ARFcom, who is afraid I may have slandered his Very Favorite Magazine:

"I want to know if the gun was a franken build and how much the mag release was threaded into the mag release button. I bet tightening it a few turns for proper engagement depth...."

Yes, it is a FrankenGun: MGI QCB upper, RRA lower, DPMS LRPK. Best I can tell, the mag catch is in spec and the malf can be attributed entirely to operator error. I promise I still like your favorite mags.

Unknown said...

If it was operator error, why are you bitchin about PMAGs? Sound like you need to keep your finger off the mag release.

Tam said...

I'm confused. Where was I "bitchin" about P-Mags?

Anonymous said...

In John's cornfused cranium, silly. :)

LycanthropeCheeseman said...

Hehe... I've done the same thing with an extended 1911 mag. Popped the little stop doodad right off. The mag continued up into the action, jamming everything up significantly.

Let us know what Magpul says. I think they like it when things break as it gives them a rare chance to improve things.