Long term magazine storage.

[D.B. Cooper]

I know that for magazine-fed guns, the magazine is the weakest link in the system. I know I can't leave them loaded. Will the springs eventually (and I'm talking years and years and years) go bad, even unloaded? The essence of my question is, what is the shelf life of a magazine if I leave it unloaded? If left in a non climate controlled storage unit, should I spray some sort of metal preservative on the outside? Should I just disassemble them and spray everything with a preservative?

 

[JohnKSa]

I've run some tests with two types of types of pistol magazines. Both tests lasted several years, one is still running now and is about 3 years along.

Mags that stay fully loaded will lose some spring strength but so far none of them have lost enough to malfunction. I took the mags from the first spring test and all of them fed properly and even locked the slide back every time even after having been fully loaded for over 800 days

Mags that are underloaded by two rounds lose noticeably less spring strength than mags left fully loaded.

Mags that are cycled but not left loaded lose noticeably less spring strength than those left loaded.

Unless the mags get very hot or visibly corrode, I can't think of any reason that a decent quality magazine would degrade in any way from being stored unloaded.

I only tested two magazine types, and only pistol mags, so I wouldn't assume that these results apply across the board. The best answer to this question is to check your equipment periodically to make sure it still functions.

 

[GunnyUSMC]

I have heard over the years that by loading a mag with to less rounds helps the mags last longer. This may help with cheap mags, but no effect on good gags other then reducing the loaded ammo you carry.
I carried 9 well used 30rd M16 magazines, each loaded with 30rds. They pretty much stayed that way for six months and when deployed, worked flawlessly.
I have also carried Glock magazines fully loaded for years. The longest were three G22 Gen3 mags. They remained loaded for 5 years, othen replacing the ammo every two years. These mags were used as duty magazines and carried daily.

 

[mag1911]

Magazine, and other, springs loose strength from cycling. New high quality springs take a set after initial use but maintain that length for a long time. Downloading magazines puts less stress on the spring. Buy high quality magazines and some extra high quality replacement magazine springs to store with the magazines and you should be fine. I use Wolff springs and have never had a problem.

For medium term storage I like Breakfree CLP and ziplock bags. For long term storage I like VCI paper and doubled up ziplock bags. Someday I'm going to try VCI paper and my wife's vacuum food sealer. The military stores magazines this way and I've seen magazines packed in the 1960s opened and no rust. I've never tried this particular brand but use something similar:

https://www.amazon.com/Armor-Protective-Packaging-A30G0404-Non-Ferrous/dp/B00KF57W56

Edit to add: The military magazines weren't vacuum packed but heat sealed in plastic film. I figure the vacuum pack won't hurt.

 

[MachIVshooter]

It depends on the magazine design, but many have the spring slightly over-compressed when fully loaded. Over-compression does take a toll on springs.

Single stack magazines generally are not over-compressed when fully loaded, so I leave them at full capacity.

Many double column magazines are near or beyond full compression when fully loaded, so I store them slightly downloaded, reduced by 2 or 3 rounds in handguns and 5 in higher capacity rifle mags; 15 rounders with 12-13 in them, 30 rounders with 25.

 

[JohnKSa]

Magazine, and other, springs loose strength from cycling.

I've heard this a lot, but that is not what happened in the test I performed. The mags that were cycled lost less spring strength than the ones that were left loaded.

New high quality springs take a set after initial use but maintain that length for a long time.

I've heard this a lot, but that is not what happened in the test I performed. The amount of spring length lost certainly reduced from measurement to measurement as the test went on, but it did continue to progress slowly even after the initial "set".

This may help with cheap mags, but no effect on good gags other then reducing the loaded ammo you carry.

It might be accurate to say "no practical effect", but there certainly was a measurable effect in the two types of mags I tested. They still worked fine after years of being left fully loaded, but the springs were measurably weaker and shorter from being left loaded, and the weakening/shortening continued to progress, albeit slowly, all the way through the test.

Again, I only tested two brands of pistol mags, so it's possible that some brands/types may not behave identical to the mags I tested. Furthermore, although my tests did not result in FUNCTIONAL degradation (the mags still worked) it is not difficult to find examples of people who have had mags stop functioning properly from being left loaded for very long periods.

The best approach is to periodically test your equipment to insure it is still functioning properly.

 

[rpenmanparker]

For those of you interested in such long term testing, be aware there is a physical phenomenon known as time-temperature superposition. Basically the time to a physical change or result normally decreases as the temperature increases. This can be used to significantly shorten the testing time. Here is a brief description of a possible way to perform the experiment.

FOR LOADED MAGAZINES USE ONLY SNAP CAPS OR SIMILAR NON-FUNCTIONAL BULLETS TO LOAD THE MAGAZINES. YOU WOULDN'T WANT TO SUBJECT LIVE AMMUNITION TO ELEVATED TEMPERATURE.

You must start with "perfectly" functioning, validated, magazines, i.e. ones that have been shown to function without any jams or failures for a certain (you pick) number of cycles, say 500 rounds. They have to be all the same brand and model, and all new, never used exceptnfor the validation, at the start of the test. You should have multiple magazines in the test for each condition. Averaging of say three or five results will give a much more useful conclusion than just testing a single magazine.

Load up say 9 VALIDATED magazines with Snap Caps and label them with the temperature condition they will be stored at. Store three of them at 40 deg C, three of them at 50 deg C, and three of them at 60 deg C. To keep the cleanliness variable fairly constant without a lot of work, do not clean any of the magazines over the entire course of the experiment including following the 500 round validation. Let the dirty condition just be standard for the test.

At weekly intervals let all the magazines cool down to room temperature and fire a set number of live rounds from each one, say two full magazine loads. The ammunition must be the same brand and SKU for the entire test. It might be wise to buy all the ammunition you are likely to need in advance and mix it all together for consistency.

If a failure of any kind occurs, remove that magazine from the test and record storage temperature and time to failure in weeks. Reload the remaining magazines with the Snap Caps and return them to their elevated temperature storage conditions. Repeat the storage and testing until all the magazines have failed.

Then average the time to failure of the three replicates of each temperature condition. Plot the average data this way: the average time to failure on the Y-axis and the storage temperature on the X-Axis. Draw a smooth curve through the three points and extend the curve back to room temperature or your usual storage temperature. The time on the X axis that corresponds to room temperature is the projected useful lifetime of that brand/model magazine assuming it was "perfect" to begin with. The time to complete the experiment should be much shorter than just real time/temperature storage.

Simple, huh?

 

[JohnKSa]

I did my testing at room temperature and performed the spring length measurements and spring strength measurements with a spring tester.

I started with new/unused OEM (not aftermarket) magazines.

I agree that testing a large number magazines would provide more accurate test results, but frankly, the goal of my test wasn't to precisely characterize the degradation, it was simply to determine if any degradation was taking place. Also, storing half dozen mags away in various states of loadedness and disassembling them to measure the springs from time to time was a simple problem to solve. Storing/testing several times that many was more complicated than I wanted to undertake.

 

[danez71]

I've run some tests with two types of types of pistol magazines. Both tests lasted several years, one is still running now and is about 3 years along.

Mags that stay fully loaded will lose some spring strength but so far none of them have lost enough to malfunction. I took the mags from the first spring test and all of them fed properly and even locked the slide back every time even after having been fully loaded for over 800 days

Mags that are underloaded by two rounds lose noticeably less spring strength than mags left fully loaded.

Mags that are cycled but not left loaded lose noticeably less spring strength than those left loaded.

Unless the mags get very hot or visibly corrode, I can't think of any reason that a decent quality magazine would degrade in any way from being stored unloaded.

I only tested two magazine types, and only pistol mags, so I wouldn't assume that these results apply across the board. The best answer to this question is to check your equipment periodically to make sure it still functions.

This supports what I've been saying for many yeeaarrrs now and have posted tech data several times to support what I've said.

Springs degrading only from being cycled is a parroted myth.

If it were true, we'd be seeing recoil springs being replaced at a 10:1 to mag springs... at the very least.

Leaving them fully loaded can and does effect them.

How much of either is dependent on many factors of which probably the most influential in a pragmatic sense is how far is it compressed in to its elastic range. (Think high capacity in compact designs; not full size 1911s, BHP, full size glocks etc)

I say pragmatically because Most gun springs are made from pretty darn similar materials, and temperature isn't too much of a factor because we humans shoot in a fairly narrow temp range as compared to the springs material temp range. Thats not meant to take away from the post above about accelerated life test but to point out that 50C is only about 122F. I've shot at that ambient temp many times when I lived in western AZ. 60C is about 140F. The accelerated life tests I've posted I think started around 75F as the base line and then around 150, 180 and 210F as the data points. And time does play a part in it.

The engineer I worked with at Hughes Space and Communications in El Segundo CA basically said that, general speaking, coil springs only compressed about 25% essentially have an infinite cycle life.

In a practical sense, this is played out in real life with engine valve springs which are compressed no more than 1/4" (that's a pretty agressive cam) on a spring thats around 2" long so we're talking only around 10-15% compressed on a pretty robust spring.

My GMC 5.3L truck has over 500 hrs on the motor (yes, it has an hour meter). If I'm averaging 1500 rpms X 60 minutes in an hr = 90000 X 500 hrs = 45 million revolutions aka cycles on the springs in temp range of... don't known what the temp is under the valve cover is but... maybe 175 F, maybe more.

As a practical experiment, go get a valve spring at the auto parts store if you can even find one because they pactically never fail... or a mag spring, and compress it 95 to 100% and leave it there for a week and look at what happens. It probably won't be functional in its respective application.

Enough rambling and on to the OP questions


If you're in AK I'm going to guess fairly near the ocean and some humidity so spraying them is probably a good idea for longer term unmonitored storage.

The mags shouldn't need to be disassembled but it can't hurt.

 

[Art Eatman]

My father gave me an ammo can with 11 bringback semi-autos. Luger, P-38, Radom, 1911, a couple of Walthers, a couple of Mausers and a Lilliput .25 and some others. All the mags were fully loaded.

They all functioned quite nicely, even after right at 40 years of storage.

 

[wally]

I kept an old Jennings 380 in my toolbox in the garage for when I was working out there at night. Things changed and that toolbox sat unused for over 10 years, rediscovered one day while reorganizing stuff. I took that Jennings 380 out to the range for grins after sitting loaded for all those years, no lube, never touched during all that time until I took it to the range. Guess what? it functioned perfectly. All round fired, fed and ejected.

If a cheap Jennings magazine isn't damaged sitting loaded for years, I don't think there is anything to worry about with any quality magazine.

My only recurrent magazine spring issues are with my Para P-14 mags, These springs do seem to lose strength fairly rapidly with use, but sitting loaded doesn't seem to matter its the number loading/shooting cycles that make the difference. The Wolfe replacement springs do seem to last significantly longer than the Para originals did.

 

[Tommygunn]

Magazines springs seem to do well in storage. I've read of old MP-40 magazines from WW2 being found, still loaded, decades after the war, that were fired, and they worked flawlessly.

Cycling them does wear the springs .... but then any machine wears from use, some faster than others.

 

[GunnyUSMC]

I kept an old Jennings 380 in my toolbox in the garage for when I was working out there at night. Things changed and that toolbox sat unused for over 10 years, rediscovered one day while reorganizing stuff. I took that Jennings 380 out to the range for grins after sitting loaded for all those years, no lube, never touched during all that time until I took it to the range. Guess what? it functioned perfectly. All round fired, fed and ejected.

If a cheap Jennings magazine isn't damaged sitting loaded for years, I don't think there is anything to worry about with any quality magazine.

My only recurrent magazine spring issues are with my Para P-14 mags, These springs do seem to lose strength fairly rapidly with use, but sitting loaded doesn't seem to matter its the number loading/shooting cycles that make the difference. The Wolfe replacement springs do seem to last significantly longer than the Para originals did.

I’m amazed that the Jennings380 worked perfectly.

 

[Art Eatman]

Longevity/durability is a function of the quality of the steel in the spring. Think about the number of cycles of operation of an automobile valve spring. And museum cars, unused for years, still run smoothly when fired up and running.

 

[MachIVshooter]

In a practical sense, this is played out in real life with engine valve springs which are compressed no more than 1/4" (that's a pretty agressive cam) on a spring thats around 2" long so we're talking only around 10-15% compressed on a pretty robust spring.

My GMC 5.3L truck has over 500 hrs on the motor (yes, it has an hour meter). If I'm averaging 1500 rpms X 60 minutes in an hr = 90000 X 500 hrs = 45 million revolutions aka cycles on the springs in temp range of... don't known what the temp is under the valve cover is but... maybe 175 F, maybe more.

Valve springs in typical push rod V8s are compressed far more than 1/4", and are already at about 25% compression when the valve is closed (why you need a spring compressor to remove the stem locks from the retainer). Valve lift is around .450" for a stock cam, .480"-.500" for an "RV" type cam, .500"-.550" for a street strip cam and full race cams can exceed .600".

Your cylinder head temperature is gonna run closer to 250° F.

Also remember that each valve spring cycles ever other engine revolution.

Using some average vehicle speeds and engine RPMs for combined city & highway driving, a vehicle with 200,000 miles will have seen around a billion engine revolutions. Yet broken or severely weakened valve springs are pretty uncommon.

 

[hdwhit]

D.B. Cooper wrote:
I know I can't leave them loaded.

Why not?

I don't recommend people leave polymer magazines loaded because of a feature of all plastics known as "creep" in which dimensional changes occur over time when subjected to a constant load that can be sufficient to cause a malfunction.

Will the springs eventually (and I'm talking years and years and years) go bad, even unloaded?

Yes. All metals; even chromium and nickel alloys will eventually succumb to environmental degradation (even gold can be dissolved under the right conditions), but in an unloaded magazine, the process will take so long that it will likely only be a concern of your heirs.

Springs are much more liable to failure when they are subject to repeated enough compression/relation cycles to cause metal fatigue. Unloaded in a magazine, a modern spring should be considered to have a shelf life in the decades.

The essence of my question is, what is the shelf life of a magazine if I leave it unloaded?

It depends entirely on the materials used and how the magazine is constructed.

• I have about a dozen 30 round M1 Carbine magazines that were not government issue, but came from third-parties (where is anyone's guess). Within about two years the springs had deteriorated so badly they would not lift the last few rounds up to the feed lips.
  
• At the same time, I have Korean made 15 round M1 Carbine magazines whose wrapping are dated during the Vietnam era that have keep kept loaded since I got them in 1977 and they still function flawlessly (although they now contain 5.7mm Johnson rounds instead of 30 Carbine).

So, to answer this question; somewhere between 2 years and 50 years.

If left in a non climate controlled storage unit, should I spray some sort of metal preservative on the outside? Should I just disassemble them and spray everything with a preservative?

I do not use spray lubricant/preservatives on my guns or accessories.

I keep most of my magazines in my garage.

Except on polymer magazines (for which I do nothing), I disassemble a new-to-me magazine and thoroughly clean it and lightly oil it inside and out and then put it back together. If the magazine gets immersed in water or mud, I will disassemble it, clean it and re-oil it. Otherwise, every decade or so, I will go back and reoil the outside of the magazine.

I don't use spray lubricants because most of them contain petroleum distillates that can migrate. There are documented cases of penetrating oils and preservatives like WD-40 causing misfires. This is usually attributed to the oil "deactivating" the primer, but since lead styphnate is not soluble is most oils, that seems to me to be fanciful. I think it is more likely that oil and penetrant contamination causes misfires by cushioning the primer compound when it is forced against the anvil by the firing pin strike.

 

[Walkalong]

Springs don't like to be compressed past their design limit. The farther you compress a spring (Cycles) the shorter the life.

 

[chicharrones]

Unless I've missed something, every mag spring mentioned so far are coil types.

I've wondered about the zig-zag shaped leaf springs in bolt guns with internal magazines? Some detachable bolt gun magazines have the same type of zig-zag spring.

 

[BSA1]

I know that for magazine-fed guns, the magazine is the weakest link in the system. I know I can't leave them loaded. Will the springs eventually (and I'm talking years and years and years) go bad, even unloaded? The essence of my question is, what is the shelf life of a magazine if I leave it unloaded? If left in a non climate controlled storage unit, should I spray some sort of metal preservative on the outside? Should I just disassemble them and spray everything with a preservative?

D.B. Cooper,

Since you ask about years and years and years I am assuming you are prepping so I will give you something more to worry about. Typically a magazine is composed of five parts; The magazine body or shell, base or floor plate, feed lips, follower and the spring. I will address each one in order.

1. Magazine body or shell.

The quality and grade of steel can vary greatly especially with foreign made mags. I have a blue Star magazine that one exterior side rusted regardless of what oil or grease I put on it. No matter how many times I cleaned, degreased and reoiled / greased it and how I stored it it would rust again in a short time period of a few months. I finally sanded it down thoroughly removing all traces of the bluing and high spots, degreased and cold blued it. The steel did not take the cold blue well leaving it different colors. However I applied a light coat of oil and it has never rusted again even over many years (probably somewhere around 25+ years).

A bigger issue is how well the back seam is welded together. Weld on the inside of the body can cause the spring to drag against it. Weak welds can cause the magazine seam to split apart. Difficult to fix and is trash can clutter.

2. Magazine or floor plate.

I have seen plastic floor plates crack and break. Goes without saying that if the floor plate fails everything inside the mag is going with it. The floor plate on some mags are welded or stamped into place and are not replaceable.

3. Feed lips.

The feed lips are probably more important than the spring. It must present the cartridge at exactly the right angle and position to feed into the chamber without jamming. Feed lips are greatly affected by the quality of the steel of the mag body to hold it's shape correctly over thousand and thousands of rounds being pressed up against it. I have seen on many occasions that the steel in the mag body has cracked from the pressure of the bullets pushing against the feed lip.

4. Follower must be of correct shape and designed not to tip. The follower tipping has been a problem with AR-15 magazines in the past.

5. The lastly the spring. It is easy to focus on the spring as it is easily replaceable. Wolff is a great manufacturer of replacement springs. It is my standard procedure to replace the springs whenever possible in all used magazines I acquire.

I like US GI Military Surplus ammo cans for long term shortage of a lot of my shooting gear. As long as the rubber seal is in good condition and the can is not too beat up you can store gear for decades. I would grease the mags inside and out with RIG grease, put them in zip lock snack bags, then in a metal ammo can and relax. In addition to be a good prepper buy some Wolff springs just to have on hand.

 

[danez71]

Valve springs in typical push rod V8s are compressed far more than 1/4", and are already at about 25% compression when the valve is closed (why you need a spring compressor to remove the stem locks from the retainer). Valve lift is around .450" for a stock cam, .480"-.500" for an "RV" type cam, .500"-.550" for a street strip cam and full race cams can exceed .600".

Your cylinder head temperature is gonna run closer to 250° F.

Also remember that each valve spring cycles ever other engine revolution.

Using some average vehicle speeds and engine RPMs for combined city & highway driving, a vehicle with 200,000 miles will have seen around a billion engine revolutions. Yet broken or severely weakened valve springs are pretty uncommon.

I don't want to derail the thread and get too far off topic so if you don't mind, can you PM me how you got to that billion revolutions # ?

And funny you said 200k miles. Mine is about to turn 170k

What's crazy to me is that the last time I checked the hr meter and mileage, I was averaging a paltry under 30 mph. Crazy.

You're absolutely correct that spring is compressed more than I said. I was thinking a 202 chevy cam but forgot all about the rocker arm ratio and I also forgot about 2 revolutions issue. And I'm pretty sure the spring is longer than 2" too but it doesn't matter. It's been a loooong time since I helped rebuild an engine.

In the end though, you're validating my point.... it's not only cycles that kills springs.

Thanks for the corrections and PM me how you got to that billion revolutions # so I don't ruin the thread with off topic.

 

[D.B. Cooper]

D.B. Cooper,[...]I am assuming you are prepping[...]

Uh. I just asked a question about the shelf life of magazines and how best to store them. Never said anything about prepping. But I appreciate the additional info you added; you're right, I was focused on the springs. (By the way, I believe prepping and SHTF type topics are off limits at THR.)

 

[D.B. Cooper]

I appreciate all the input from all of you guys. Many thanks.

 

[stchman]

I've had a pistol with the mag loaded for years, I took said pistol out and it functioned just fine.

 

[NIGHTLORD40K]

This supports what I've been saying for many yeeaarrrs now and have posted tech data several times to support what I've said.

Springs degrading only from being cycled is a parroted myth.

If it were true, we'd be seeing recoil springs being replaced at a 10:1 to mag springs... at the very least.

Leaving them fully loaded can and does effect them.

How much of either is dependent on many factors of which probably the most influential in a pragmatic sense is how far is it compressed in to its elastic range. (Think high capacity in compact designs; not full size 1911s, BHP, full size glocks etc)

I say pragmatically because Most gun springs are made from pretty darn similar materials, and temperature isn't too much of a factor because we humans shoot in a fairly narrow temp range as compared to the springs material temp range. Thats not meant to take away from the post above about accelerated life test but to point out that 50C is only about 122F. I've shot at that ambient temp many times when I lived in western AZ. 60C is about 140F. The accelerated life tests I've posted I think started around 75F as the base line and then around 150, 180 and 210F as the data points. And time does play a part in it.

The engineer I worked with at Hughes Space and Communications in El Segundo CA basically said that, general speaking, coil springs only compressed about 25% essentially have an infinite cycle life.

In a practical sense, this is played out in real life with engine valve springs which are compressed no more than 1/4" (that's a pretty agressive cam) on a spring thats around 2" long so we're talking only around 10-15% compressed on a pretty robust spring.

My GMC 5.3L truck has over 500 hrs on the motor (yes, it has an hour meter). If I'm averaging 1500 rpms X 60 minutes in an hr = 90000 X 500 hrs = 45 million revolutions aka cycles on the springs in temp range of... don't known what the temp is under the valve cover is but... maybe 175 F, maybe more.

As a practical experiment, go get a valve spring at the auto parts store if you can even find one because they pactically never fail... or a mag spring, and compress it 95 to 100% and leave it there for a week and look at what happens. It probably won't be functional in its respective application.

Enough rambling and on to the OP questions


If you're in AK I'm going to guess fairly near the ocean and some humidity so spraying them is probably a good idea for longer term unmonitored storage.

The mags shouldn't need to be disassembled but it can't hurt.

This. In 23 years of professional automotive service, I have seen exactly 1valve spring fail on a stock engine- and that was a brand new vehicle with 60 miles on the clock, so manufacturing defect, not a wear issue.

 

[caribou]

Ruger 10/22's are popular.

Just throwing out that a quick example to test is a Ruger 10/22 standard 10 round magazine.

''Clock spring'' type, If I rememeber correct like.

Load it and wait a week. The first, maybe second rounds will load , then the springs tension become so weak that they cannot advance the shells fast enough for the bolt to pick them up.

The newer Ruger 15 shot mags are single stack, and can stay loaded full for months with out spring problems. Unlike the 10 rounders, the 15 project out of the guns pretty far, but who cares when they work as well as they do.