Heard a new (to me) reason not keep mags loaded

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DeepSouth

DeepSouth

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First off I'll admit I always keep all my mags loaded, fully loaded. I figure an unloaded mag is a useless one, so I keep them all loaded. Whether it's a pistol mag, an AK mag, or a hunting rifle mag it doesn't matter. To me an empty (and therefore useless) mag means I need more more ammo. I have heard the age old "the springs are going to get weak" argument many, many times and obviously I disagree.


But anyway I had someone tell me I shouldn't leave mags loaded because the pressure from the spring pressing the top round into the feed lips can eventually bend the feed lips and make the mag have feeding issues. I'm not saying I don't believe it (yet) but when I look at most feed lips this argument doesn't seem too likely. Especially with my AK and 1911 mags, I just don't see it. Even with my other mags it just doesn't look likely.

Just wondering what ya'll think. Ever had feed lips damaged by leaving a mag loaded, ever heard of it happening? I don't see me unloading my mags anytime soon.
 
Never had the feed lips on a loaded mag affected during storage. On the other hand, MagPul AR magazines come with a cover that snaps over the top of a loaded magazine and takes pressure off the feed lips. Whether they are needed or not, I don't know.
 
A good quality magazine made of properly heat-treated steel is engineered to withstand the tension of being topped off for years. I was personally involved with a Colt Commercial Government Model that was stored in an attic fully loaded in Condition One for over 60 years, and it functioned perfectly when I fired it...with the ammunition that was in it.


Junk gun show and bargain-basement magazines? All bets are off.
 
Ever had feed lips damaged by leaving a mag loaded, ever heard of it happening? I don't see me unloading my mags anytime soon.
Click to expand...

I've only heard that in reference to AR mags...the aluminum ones. It does make you wonder why MagPul added the lip saving covers
 
My "work" AR has 3 loaded mags in its case all the time. They get unloaded at the range twice a year during qualification. They are going on 10 years old and have given me no troubles, yet.
 
Just load that puppy up less 3 rounds and dont worry about it.

Spring will not be fully engaged (compressed).
 
I've just heard this argument within the week. It was either on THR or a gun blog. The argument was in reference to the plastic mags like pmags. I don't have any plastic mags to confirm or deny.
 
It would make sense that he got his info from AR guidelines or such. He is a pretty big AR guy. I will have to take a closer look at an AR mag next time I have one in hand. I don't have one....Yet.

I have heard (which means I don't know) some of the older aluminum AR mags were pure junk, some even considered "disposable" after the first use. Don't know if there's a connection but it sounds at least plausible.
 
I haven't heard about deforming feed lips, but what I have heard, and it seems possible, is if you have a detachable mag-fed semi auto shotgun, that if you have the mag full and under a closed bolt, over time it might deform the plastic shell of the top-most round, but really only if its shot and not a slug. That seems to make some sense, so they say if you must do that, keep the bolt open. For rounds that use metal cases I doubt it.
 
No.

If you do not yield the steel or heat it, pressure for extended periods of time will not deform it. Same reasons that leaving your mag loaded won't hurt the spring.
 
Plastic deformation is only a factor with plastics, very thin metals, and very hot metals.
 
i have p mags. the top cover of at least 6 of them i left loaded, will not stay on. it is like the cover fatigued and is now junk. when you press it on a full mag, it pops right back off. but, they still work, after being loaded for about a year.
 
This is referring to an AR15 magazine, isn't it?

Springs are worn out by flexing, not being compressed or expanded. Leaving your magazines loaded or empty will not hurt them. But moving the spring a bunch will.

Is steel or aluminum tougher than brass? In today's modern machining, probably not. You're more liable to see damage to the round than the magazine.

I've heard this one before, and I think it's a myth started by someone because they don't like loaded magazines around.
 
plastic magazines with no metal lips may have an issue. Steel won't, and I don't think aluminum will either.
 
I don't envisage a compressed spring or stressed piece of metal deteriorating unless the stress is very, very close to the yield stress, in which case there could be creep processes that would cause failure even in the absence of any external stress. In other words, if your magazine has been properly designed and its design verified, you can leave it fully loaded. I would test your magazine by storing it fully loaded and test firing it every month or two. If you do this for a few months, and it works OK, it will probably be good for ever.
 
DeepSouth said:
I have heard (which means I don't know) some of the older aluminum AR mags were pure junk, some even considered "disposable" after the first use. Don't know if there's a connection but it sounds at least plausible
Click to expand...
Unless there has been some change my understanding is that all aluminum magazines are considered disposable. That was quite a shock, back in the day when H&K-91 mags were $45
 
Yes, this actually is a little understood problem with keeping your magazines loaded all of the time. All it takes is 10, 15 million years at the most under tension and those mag lips are going out of shape by 2 or 3 mm easy. Might as well throw them away at that point, nothing much you can do.
 
killchain said:
Springs are worn out by flexing, not being compressed or expanded. Leaving your magazines loaded or empty will not hurt them. But moving the spring a bunch will.

Is steel or aluminum tougher than brass? In today's modern machining, probably not. You're more liable to see damage to the round than the magazine.

I've heard this one before, and I think it's a myth started by someone because they don't like loaded magazines around.
Click to expand...
The term you're looking for is fatigue. Fatigue is the cyclic application and relief of a stress. In metals, fatigue causes hardening and embrittlement.

Properly engineering spring steels do not suffer pronounced amounts of creep/stress relaxation. That's why as stated, good mag springs can stay safely loaded for a very long time. Hence, why an individual shooting thousands of rounds in a few months will cause more wear and tear on the mag-springs than a guy who leaves loaded mags in his safe for years.

And to clarify another definition, "toughness" is the ability of a material to survive impacts. Imagine hitting a diamond with a hammer. Obviously, the diamond will shatter, even though it's much harder than the steel-faced hammer. Tough is the opposite of brittle.

In the case of "cartridge damage", yes, the brass is more susceptible to wear than a steel or aluminum follower. But this is unlikely. As is crem/impact/compression damage to the rounds.
 
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