Do Mags loaded for 3 months ruin the MAG?


February 23, 2009, 09:28 PM
I keep some Rifle and pistol mags loaded in my safe for long periods of time. Does this mess up the mags reliability? Should I keep them loaded and ready or just a few? I just don't get the time to shoot enough.

If you enjoyed reading about "Do Mags loaded for 3 months ruin the MAG?" here in archive, you'll LOVE our community. Come join today for the full version!
February 23, 2009, 09:31 PM
No. A spring kept under tension will not lose its strength over time.

February 23, 2009, 09:32 PM
maybe weakens the spring a bit if they are filled to the max, but my wilson combat mag in my carry pistol has had 7 rounds in it for 6 months.

every few weeks i empty the carry ammo and shoot with it and no probs yet.

February 23, 2009, 09:34 PM
In one word No. Some claim that over time the springs weaken others say not. With todays metallurgy I believe the latter. I've got a car with 200,000 miles on it and the valve springs still work as do all the other springs in it.

February 23, 2009, 09:34 PM
I usually rotate my home defense magazines for pistols, 6 months loaded/6 months empty, but I have had magazines that sat for WAY longer in the cabinet loaded and have never had one not work.

February 23, 2009, 09:42 PM
Contrary to popular belief, springs do not appreciably "creep" or get "tired" with age alone.[citation needed] Spring steel has a very high resistance to creep under normal loads. For instance, in a car engine, valve springs typically undergo about a quarter billion cycles of compression-decompression over the engine's life time and exhibit no noticeable change in length or loss of strength. But for good measure, springs can be replaced when doing a valve job. The sag observed in some older automobiles suspension is usually due to the springs being occasionally compressed beyond their yield point, causing plastic deformation. This can happen when the vehicle hits a large bump or pothole, especially when heavily loaded. Most vehicles will accumulate a number of such impacts over their working life, leading to a lower ride height and eventual bottoming-out of the suspension. In addition, frequent exposure to road salt accelerates corrosion, leading to premature failure of the springs in the car's suspension. Weakening of a spring is usually an indication that it is close to complete failure.

February 23, 2009, 09:43 PM
welcome to thr, this gets asked alot, and the answer is simply no, in quality mags they will be fine, for crap aftermarket i can not speak for, but any good factory mags, from the major players in the industry you will be good.

February 23, 2009, 09:45 PM
heres how i found that

fireman 9731
February 23, 2009, 09:51 PM
I have always heard that its the compression/decompression cycle that wears springs out. Keep them loaded or keep them unloaded, but doing both frequently is what wears them out.

February 23, 2009, 09:55 PM
I keep alot of mine fully loaded and have used them for more than 10 years with no problems.

February 23, 2009, 10:15 PM
I inherited some AR mags that were filled for >30 years and they function just fine.

February 23, 2009, 10:40 PM
This is what I thought......

Fully Loaded or Unloaded = No effect.

Constantly loaded and loaded (ie. Firing) = Wears them down.

I thought the "use" of the spring is what wears it down.

I could be wrong though.


February 23, 2009, 10:42 PM
No, just rotate them every once in a while and you'll be good.

February 23, 2009, 10:44 PM
Btw I've had Glock mags stored for over a year and shot them the other day and they worked just fine.

February 23, 2009, 11:07 PM
Magazines? I thought everyone used single shot rifles and pistols these days... learn something new every day I guess :D

Kind of Blued
February 24, 2009, 02:25 AM
No, just rotate them every once in a while and you'll be good.

Did you read any of the dozen posts before yours? Your recommendation will wear springs out FASTER than if one loaded some mags and just left them, for years, and years, and years.

This question is asked all the time here, and it's always the same answer, but people refuse to believe it and add in their own bit of grey area for good measure. Thus, it lives on.

February 24, 2009, 02:49 AM
No. A spring kept under tension will not lose its strength over time. Partially true. They can weaken depending on if they are exposed to the elements. If there is corrosion or other things going on they could be affected. Extreme heat or cold could also cause issues. Overall for most people its never going to be a problem.

With todays metallurgy I believe the latter. I've got a car with 200,000 miles on it and the valve springs still work as do all the other springs in it.

I have built a few engines, and most of my friends are into racing. A stock engine will likely have springs that will last a few engine rebuilds. However when it comes to racing valve float becomes an issue with stock springs, and springs that have been used for a while. The pressure a valve spring provides does change on a engine over time. In the case of a stock engine with typically large piston to valve clearences, low rpm (read under 5,500 rpm) and so on, it really wont be an issue. Any minor change really wont be a big issue, even more so since most car engines rarely operate in the 5K plus rpm range. On a engine that sees racing, has closer Piston to valve clearences, higher rpm for longer, more agressive cam profiles that require the valve to shut faster, etc a slight loss of pressure could mean a diaster. Its the main reason why your not going to see racers reusing parts that see a lot of abuse.

In the case of mag springs they are typically overpressure then the minimum to feed rounds properly. A minor pressure decrease is not going to be a big deal. Hell they will probably still work with a 15% loss in pressure or more.

February 24, 2009, 02:59 AM
It's cycling that wears out modern springs, not being kept in a state. While it was true a very long time ago that metals, kept under tension, would eventually start to permanently warp, today's tempering techniques have all but eliminated that.

Highland Ranger
February 24, 2009, 08:25 AM
I have had an HK usp loaded since 1993 - still shoots fine.

February 24, 2009, 09:38 AM
Beats me, i think it depends on alot of things, but the question is timely for me.

I inadvertently had a long term expirement brewing as the result of a few relocations and life going on that has prevented me from shooting for some years.

I have two chip mcormick 8 rounders for my 1991A1 commander. With no exageration whatsoever, those two magazines have been loaded, 8 rounds each, since late 1999, just short of 10 years.

Two saturdays ago(valentines day), part of my safety checkout for a new range, I brougt those loaded mags ran 50 rounds through both with no failures.

Last fall, I did the same with a US GI 30 round AR magazine. It had been loaded with 20 rounds for the same time frame. It functioned perfectly for the 20 rounds that were in it and 200 more that day.

I can't say if this was just luck or not, but it seemed to demonstrate, that at least for those three mags, leaving them loaded doesn't matter.

February 24, 2009, 09:52 AM
Springs weaken from repeated loading and unloading. Most of the mags for my .22 were fully loaded for about a year. Been two years since then and they still function flawlessly.

Load 'em up and don't worry bout it.

February 24, 2009, 09:58 AM

February 24, 2009, 11:02 AM
There have been lots of threads about this subject. Magazines have been found left loaded since WW2 that still functioned OK.
As others have said, it's the continued cycling that wears them out, not consistant compression.

February 24, 2009, 11:07 AM
I recently found a WWII 1911 mag that I left loaded since 1974.
It worked fine when I shot the 7 rounds.

Good quality springs last indefinitely when compressed.

The only other issue is if the spring is too strong, like some recent 8 rounder attempts. The feed lips will expand from the pressure and mess up the mag.

February 24, 2009, 11:09 AM
I keep some Rifle and pistol mags loaded in my safe for long periods of time. Does this mess up the mags reliability? Asd has been discussed, storing magazines fully-loaded will not harm the springs,


The spring is not the only part of the magazine. There is a body to consider, as well.

Some magazine designs (e.g. USGI AR-15 mags) reportedly have relatively weak and/or brittle feed lips. Storing well-used magazines fully loaded can put enough pressure on the lips to cause cracking. I have not had this happen to me, but I have heard several reports of this sort of feed lip cracking and can readily accept it as a possibility.

Byron Quick
February 24, 2009, 11:11 AM
I haven't witnessed it but I've heard others relate of military magazines that had been loaded for decades that still functioned perfectly. Both ammunition and magazines.

February 24, 2009, 12:23 PM
jcwit That is prolly the Best answer to this Never-ending Question. Yes Valve springs do fail but only after several Billion cycles.

February 24, 2009, 06:05 PM
I took apart a few magazines and I noticed the springs had different lengths. This might effect feeding reliability. YOu can always just pull the spring back to the proper length. I personally break down all magazines that I'm not using in the foreseeable future.

February 25, 2009, 12:48 AM
I had to giggle a little when I read this title.

If it's a US made Beretta 92FS sure will ruin it, even if you exercise the old LEO trick of leaving 1-2 rounds out so the spring isn't at full compression and rotate through mags every 2-3 weeks. We were lucky on my last deployment and were able to trade with the Italians to get some quality mags...had ammo in them for over 6 months, rotating every 2-3 weeks.

I've only had a handfull of AR mags give me problems, even after being loaded for nearly an entire year long deployment in the sand. AK mags can be tempermental from time to time, but I have yet to figure out why.

I've only had 1 Glock mag fail (PD officer I bought the gun from kept it fully loaded as a back-up).

It's just good practice to rotate mags in and out of use, especially so you can clean and lubricate them. Metal springs still need rust treatments in most cases. (even alloys)

February 25, 2009, 11:38 AM
Old wive's tale and something for gun writers to write about to fill their monthly column. Yes, coil springs will lose some of their strength over time when cycled REPEATEDLY. For example, valve springs in engines. How many times have you ever heard of someone having to have their valve springs replaced because they lost tension?

February 25, 2009, 11:46 AM

The shooting sports are full of some of the most knowledgeable and capable people you'll meet anywhere. I've been impressed consistently with the abilities of those I meet at the range to diagnose and fix a gun problem with as little as some spray lube and a cotton swab. However, sometimes a myth will creep into the folklore.

The magazine spring myth has been around for many years and is growing in popularity. It goes something like this: "You should unload your magazines when they're not in use or the spring will weaken causing failures to feed." This has gone as far as shooting competitors actually unloading their magazines between stages to extend the life of their springs. A variant of this myth is: "You should never load a magazine to capacity and should always leave it one round short." What if you need that round some day?
Recently, I read an article in a gun magazine suggesting you rotate your magazines so the ones not in use can "recover and rest." The same author uses the phrase "spring-set" to describe weakness of a spring because it was compressed for a long time. Hogwash. There's nothing further from the truth. Springs don't care how long they're compressed and don't require rest, recreation or even a vacation from time to time.

Shameful Spring Benders

To put this one to rest, you have to understand creep. Creep is the slow flow of a non-ferric metal like copper, brass and lead under force. At temperatures outside of a furnace, steel doesn't have any appreciable creep. Under most conditions, steel flexes and then returns to its original shape. When pushed past its elastic limit, steel will bend and not return to its original shape. All designers of well-made magazines make sure the spring never approaches the elastic limit when the magazine is fully loaded. Honest. This means the spring will not weaken when the magazine is fully loaded -- not even over an extended time. Like 50 years. American Handgunner recently ran a story about a magazine full of .45 ACP that had been sitting since WWII and it ran just fine on the first try. So there you go.
Now that the light of truth is leaking out, lets talk about what is causing failures to feed. The only way to weaken a magazine spring is to flex it past its normal range (elastic limit). If this is happening, somebody is trying to overload a magazine or has "adjusted" it by bending the spring. Both of these could cause feed failures. Shame on you if you're a spring bender.

Carlton Nether, Customer Service for Beretta USA, tells us keeping a pistol magazine loaded for an extended period doesn't cause magazine spring failure, however, failures to feed can result. He says, "The ammo will 'roll' in the magazine. If the mags are kept loaded and moved around a lot -- say on a cop's belt -- the rolling action can, over time, cause creases in the cases. These creases can cause malfunctions. Also the top bullet will roll against the magazine lips and creasing can occur there as well. Just check old ammo that's been bouncing around in a magazine for a long time.

We tell police officers if they keep loaded magazines, take a few seconds to "cycle" the ammo. Periodically unload the mag and reload it in a different sequence. This movement will allow the bullets to be in different parts of the magazine and help eliminate creasing.

At STI, Dave Skinner, President and CEO says, "Personally, I rotate my 'under the bed' and 'under the seat' mags about every six months. I always empty them the 'fun' way and have never had a failure." Given what we learned above, this sounds like a good idea. Smith and Wesson customer service also says magazines can stay loaded indefinitely without hurting the spring.

As we add force onto a spring, it will displace the same amount for each amount of force we add. This is true until the spring passes a certain point called the elastic limit. Robert Hooke discovered this theory back in 1660. Hooke's Law states: "If the applied forces on a body are not too large, the deformations resulting are directly proportional to the forces producing them." Which means, in actual human being language, if we load a spring past its elastic limit, it permanently deforms. It still provides a force against the load but the force is no longer proportional. If this happens, when we unload the spring (such as when we empty a magazine that has been over-loaded) the spring never returns to a state where it can provide the same load for the same amount of displacement.

Trust Us

When a magazine manufacturer designs a spring, they plan for a preload. The spring is already compressed some in the magazine. On the curve below, this would be Point A. The spring compression would be designed to be below the Elastic Limit. When fully compressed, the spring would be at Point B. If the spring is ever compressed past the elastic limit, say to Point C, it won't ever behave the same. Like a recalcitrant lazy Uncle, it will have a lower spring force for each amount of displacement. On the drawing, the spring would now cycle between points D and E. This means that -- particularly with the last bullet or two -- the force pushing the bullet up would be less and lo-and-behold, a mis-feed might occur.
When somebody stretches your spring to "fix" your magazine, they are trying to get you back on the original curve. They may get pretty close, however, it's unlikely the spring will ever perform to its original design. The elastic limit is now shifted lower and your magazine spring may fail to perform fairly quickly.

Having said all this, if you have a magazine that isn't feeding right, what should you do? First, disassemble the magazine and clean it thoroughly. Then try it with new, factory ammunition in a freshly cleaned gun. This takes away some of the possible causes. If you are still having feed problems, send it back. Even the low cost, after-market magazine manufacturers will fix the problem at no cost to you other than shipping. If it's a magazine from the gun's manufacturer, let them troubleshoot and repair the problem. Otherwise, toss the mag. It's not worth risking your life to save a few bucks. And that's the truth.

If you enjoyed reading about "Do Mags loaded for 3 months ruin the MAG?" here in archive, you'll LOVE our community. Come join today for the full version!