PMag (and others) life cycle

[OlongJohnson]

What typically causes PMags to get retired? Obviously, driving over them with a truck would be a problem. Dropping them on the feed lips could be a problem. Beyond damage and accident, what does a PMag (or other mag) dying of "natural causes" look like?

Do feed lips get worn out? Do followers get worn out? How much does that depend on the amount of sandbox sand that's in them, versus just unavoidable wear from the brass sliding out?

Springs fatigue? Springs are replaceable. Would it make any sense to hoard some fresh ones?

I'm familiar with people updating aluminum mags with improved followers and perhaps fresh (or "extra power") springs, but it seems like that's as much about the design change as renewal, much of the time. On current-production M3 PMags, there doesn't seem to be much upgrading to do. Will springs and followers wear out before bodies?

How many rounds can someone typically put through PMags before they are toast?

And all the same questions for aluminum mags, too, I guess.

[vcdgrips]

I know I am not really answering your question. I have training mags and carry mags.
The carry mags have little mileage, maybe 50 rounds to confirm function and lock back.

Putting some back when they can be had at 10-20 per is never a bad idea.



Mags are consumables. They are numbered. Two failures to function without a discernible non mag related reason means that mag goes to the training pile FOREVER.

If I used or could likely use a carbine everyday, the allowed failure rate would be ZERO presuming I could resupply. As a matter of fact, I would change out my set the week of my birthday just to be sure.

FWIW/YMMV greatly

[RancidSumo]

I have been wondering the very same thing. Out of concern regarding the political landscape in the coming years, I've been building a supply of mag springs/etc. for my pistol mags and wondering if I should do the same for the AR. Problem is, I have not been able to find a cost effective way to do it. "Rebuild kits," or even just springs, cost nearly as much as a whole spare mag.

That said, I'm very interested in any answers people here may have regarding lifespan.

[Elwin]

Also no answers but I have a related question or variation on the same question I was thinking of starting a thread for; do people tend to change out loaded Pmags, and their ammo, and if so how often?

I have Pmags dedicated to defensive use that don’t get used at the range aside from initial testing. I’m also not chambering the rounds. Should they be on a once yearly schedule of fire all the ammo and replace with a whole second set, like I already do with pistol mags? That’s doable but if it’s not necessary I’d skip it, given the price of that many rounds of Federal Fusion MSR.

[Duelist]

Also no answers but I have a related question or variation on the same question I was thinking of starting a thread for; do people tend to change out loaded Pmags, and their ammo, and if so how often?

I have Pmags dedicated to defensive use that don’t get used at the range aside from initial testing. I’m also not chambering the rounds. Should they be on a once yearly schedule of fire all the ammo and replace with a whole second set, like I already do with pistol mags? That’s doable but if it’s not necessary I’d skip it, given the price of that many rounds of Federal Fusion MSR.

If the mags aren’t stored in a car, if they just stay at home on HD duty, I can see no good reason to shoot them up. They are just getting stored indoors in a magazine instead of in a box.

[ST911]

What typically causes PMags to get retired? Obviously, driving over them with a truck would be a problem. Dropping them on the feed lips could be a problem. Beyond damage and accident, what does a PMag (or other mag) dying of "natural causes" look like?

In the early (rev 1?) I see spine cracking, chips to the feed lips, and the limiter/nub along the inside wall breaks off. They mostly remain functional, unless the chips don't retain rounds. The M2 and M3 are better, but comparing long term wear between version won't be applicable for awhile yet. And as noted above, mags are ideally consumable, limited lifespan items. I don't think I've replaced mag springs in any. Possible, though.

I have wondered about embrittlement of the early pmags over the long haul, and I vaguely recall that being discussed here before. Still, probably an issue that's outside a normal service life when they're actually used. Kind of a moot point now anyway with the latest revisions.

Like @vcdgrips said, I have carry and training mags and limit crossover between them.

[DMF13]

I've have hear about, but not actually seen, cracking of the feed lips due to the pressure of the top round n a loaded mag constantly pressing against the feed lips. As a result I keep two mags immediately ready for use, but the rest of my loaded mags are kept with the "dust cover" in place, as that presses down on the top round relieves the pressure on the feed lips. Every few months I rotate which of my mags are the ones kept "ready," without the "dust cover" on.

After eight years with 2 dozen fully loaded PMags I haven't had any signs of cracking.

[EMC]

Have had gen 2 pmags fully loaded for over 5 years. Lips look fine. I will test fire one eventually but 5 years seems too soon. Perhaps 10 years.

[HCM]

What typically causes PMags to get retired? Obviously, driving over them with a truck would be a problem. Dropping them on the feed lips could be a problem. Beyond damage and accident, what does a PMag (or other mag) dying of "natural causes" look like?

Do feed lips get worn out? Do followers get worn out? How much does that depend on the amount of sandbox sand that's in them, versus just unavoidable wear from the brass sliding out?

Springs fatigue? Springs are replaceable. Would it make any sense to hoard some fresh ones?

I'm familiar with people updating aluminum mags with improved followers and perhaps fresh (or "extra power") springs, but it seems like that's as much about the design change as renewal, much of the time. On current-production M3 PMags, there doesn't seem to be much upgrading to do. Will springs and followers wear out before bodies?

How many rounds can someone typically put through PMags before they are toast?

And all the same questions for aluminum mags, too, I guess.

The answer is “it depends.”

It depends on your use, the conditions of storage, including heat exposure to UV light, if the mags are kept loaded, if the P mag covers are used.

I’ve only ever killed PMAGs via feed lip cracks and those can be mitigated by using the covers if storing loaded. The Magpul covers press down slightly on the ammo stack and spring transferring the load to the front and rear of the Mac instead of pushing laterally against the feed lips.

[olstyn]

Should they be on a once yearly schedule of fire all the ammo and replace with a whole second set, like I already do with pistol mags?

What's your rationale for doing it with pistol mags? Perhaps it's a naive viewpoint on my part, but outside of scenarios involving non-sealed ammo in humid climates, if the ammo doesn't go bad sitting in an ammo box, why would it go bad sitting in a mag?