Monday, April 20, 2020

Long-term storage of loaded firearm magazines

The question recently arose, in discussion with my wife and some other writers, about whether it was safe to keep one's firearm magazines loaded for extended periods (we're talking years rather than months).  There was considerable disagreement about it.

To begin with, let's clarify the discussion a little.  Here's a video analysis of how magazine springs work, and what's within their design specifications.  It looks pretty accurate, judging by my knowledge of the field (which is that of an educated and experienced firearm user, not an engineer, I hasten to add).  I don't fully agree with his conclusion, though - more about that later.

During my military service, I learned a lot from a few former US servicemen.  After the Vietnam War ended, they didn't want to go back to their homes, because of attitudes towards them in civilian society.  Several joined the Rhodesian and South African armed forces, and I'm glad they did, because what they taught helped keep me alive during some rather difficult times.  They based their comments about magazines on what they'd experienced in Vietnam.  This was, of course, with the first iteration of the M-16 rifle and its 20-round straight-sided magazines, neither of which were the world's most reliable at first.

They told us that the magazine spring had to be in good condition and free of contaminants like sand, dust or mud, which might cause friction and binding against the sides of the magazine.  Since Africa had more than enough contaminants to go around, that made a lot of sense to us.  They also pointed out that when the magazine was loaded to full capacity, the top round might protrude slightly higher than normal, due to the pressure on it from the rounds beneath it.  That could cause it to drag against the internal components of a rifle during the autoloading process, and potentially cause a misfeed.  Finally, if the magazine spring was weak or defective, it might not feed correctly under the stress and pressure of a full load.  For all those reasons, they had learned to download their M16 magazines by 10%, and recommended that we do likewise.  If we had a 20-round magazine, load it with 2 rounds less (i.e. 18);  if a 30-round, load with 27;  if a 35-round, load with 31 (ten per cent of max capacity is 3.5, which is then rounded up to the nearest whole number).

I've followed those guidelines ever since.  During my military service, carrying first an R1 rifle (a South African licensed version of the FN-FAL) and later the R4 (a ditto copy of the Israeli Galil), I always downloaded by 10%.  Even today, out of long habit, for any magazine - long gun or handgun - holding 10 or more rounds, I'll download by 10% for carry purposes and short-term storage.  In my Glock 17, for example, I load the 17-round magazines with 15 rounds (10% of capacity is 1.7 rounds, which rounds up to 2), plus one round in the chamber.

The former US servicemen went further when it came to long-term storage of loaded magazines.  Remember, their experience had been largely with the first-generation M16 magazine, the spring of which was not very strong, and could take a "set" if kept in a tightly compressed condition.  Their views were strongly ratified by several Rhodesian and South African servicemen of my acquaintance, who reported similar problems with their R1 20-round magazines.  For storage longer than a few weeks, our instructors recommended downloading by 15% to 20%, depending on the quality of the magazines concerned.  Thus, a 20-round R1 mag could be safely stored for months or years with 16 rounds in it, and a 35-round R4 mag with 28 rounds.  Again, I've followed those guidelines ever since.  Some claim that modern magazine springs are better than older ones, making downloading unnecessary.  I'm not so sure.  I work on the principle that Murphy is out to get me, and I have no way of telling how good my magazine springs may be - particularly if I don't know when or where they were made.  I'll continue to download mine, thank you very much.

I keep quite a few loaded rifle magazines on hand, not because I'm paranoid, but because it saves a lot of time.  If you've got to load 10 magazines at the shooting range with up to 30 rounds apiece for a practice session, that's an expensive process when you're paying by the hour!  I'd rather take 10 loaded magazines with me, and be good to go as soon as I reach my firing position.  I can load them at my leisure when I get home, even if I do just one every day or two.  After all, if I have to store both magazines and ammo, why not store them together like that?

I'm also a firm believer in keeping a few magazines on hand for "social use", loaded with defensive ammunition, just in case.  In my younger days, I found myself in too many situations where there was no time to load magazines.  Sometimes the fight comes to you, whether you're ready or not.  (Ask anyone who's had to survive a home invasion, or run into urban unrest while driving.)  Also, if some sort of natural disaster threatens your home - for example, a tornado, a hurricane, etc. - and you need to leave in a hurry, the press of other last-minute details means you may not have time to load magazines for security while you travel.  I keep a 'battle belt' and/or chest rig carrying loaded rifle and handgun magazines, ready for use if needed, near where I store my firearms.  All the magazines are downloaded as described above, but hold enough ammo to take care of initial needs;  and I'll have spare rounds to top them up, if I have time to do so.  If I need a gun in a hurry, all I have to do is slap in a magazine, cycle the action, and I'm ready to go.

You don't have to get complicated or expensive about the battle belt or chest rig.  Remember the KISS principle.  The more gadgets and gizmos you have on it, the more likely you are to break something or get tangled up in it.  In Africa, as a civilian, I used the old Chinese Type 56 or Type 81 chest rigs, and modified them to suit my needs.  I'd run into them often enough on African battlefields to know they're pretty tough, and they don't cost much even today.  You can cut off one or more of the pouches if necessary, and replace them with a different style of pouch - e.g. a cellphone holder, a small IFAK (medical kit), etc. - for greater versatility.  A simple chest rig like that, added to a belt holding your pistol holster, handgun magazine carrier and a flashlight, can be very useful.

Anyway, those are my thoughts on keeping loaded magazines on hand.  What has your experience been?  Do you do things differently?  Let us know in Comments, so we can learn from each other.



riverrider said...

thirty years of experience has taught me the wisdom of your words, and it's what i tell new shooters. yes, i think the newer technology will stand the full mag indefinitely but i have found that a fully loaded mag was the cause of many malfunctions, and when the first round is usually the most needed that can be a problem. why chance it? military infantry, armament repairer, trainer, and civilian armorer at a military school. and i rotate my mags that stay loaded too and give them a rest. keep lots of mags. i can't fathom people who have two mags and believe that's plenty. or one box of ammo. ugh!

Eric said...


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CDH said...

I have at least 10 different brands/styles of mags ranging from (good brand name) 20 and 30 round AR mags to 15 round Glock 40 cal and 17 round 9mm mags that have been kept fully loaded (except when shot at the range) for a minimum of 1 decade up to 2 decades with nary a spring related failure. The only mag related problems I have ever had were from new mags that had issues. Some 30 round AR mags has springs so strong that the bolt would not strip the top round if loaded to full capacity. Some 1911 mags that didn't feed properly when fully loaded. All known issues well documented...and not really spring fatigue related. While your policy of underloading is also well documented, it is also unnecessary with top shelf modern well proven equipment.

JNorth said...

As an engineer I agree that springs are not going to fail. My understanding of the issues with the early M-16 mags is it wasn't actually the springs but the feed lips getting bent. P-Mags can't bend and with the dust cover their is no pressure on them anyhow so that isn't an issue for me. I have one 1911 mag that has issues but it is a different make then all the others so that is probably the issue with it.

suburban said...

My experience is civilian not military. Worst case for dust and dirt has been a week on a dirt range. That said I found problems with some aftermarket Ruger 10-22 mags, some aftermarket S&W mags, and all aftermarket Sig mags. On the AR platform I use Magpul exclusively. With reliable mags I have never seen a problem fully loading mags and keeping them so loaded for years.

Old NFO said...

I'm going to agree with you. I download by 10% out of habit and 'training', and I have a mix of old and new mags for various weapons. Just remember, Murphy was an optomist...

Sean said...

The rifle magazines I keep continuously loaded for social situations are 4 30rnd PMags, loaded with 20 cartridges each.
The Handgun magazines are loaded to capacity, since they are cycled at a indoor range on a regular basis.

libertyman said...

Are people talking about springs? Or dust, dirt, congealed grease, balky magazine lips and other things?

Springs don't "take a set" unless you can please explain what happens to their metallurgy. If you don't exceed the elastic limit it doesn't change. This is one of those persistent talking points that gun people go over and over again.

I give you the summary of testing from Springfield Armory -- the one in Springfield Mass:

The government Springfield Armory did a study on long term storage of magazines: Springfield Armory. SA-TR11-2643 Evaluation of Pretreatment Processes And Long-Term Storage On Magazine Spring For The M14, 7.62MM, Rifle. Springfield, MA: February 01, 1966.

A permanent set occurs when the compression spring is compressed beyond its elastic limit and does not return to the original length. This results in a shorter free length but more significantly, lower spring force.

"A permanent set in a USGI M14 rifle compression spring is not formed when compressed to the minimum length and left indefinitely."

Daosus said...

There are two effects being confused here. Plastic deformation is where the spring is pushed beyond the elastic limit, as described by the poster above. This happens quickly. There is also a process called "creep" where material will take a set of left under stress for a long time. The speed at which this happens is related directly to how close the stress is to the yield stress if the material. Modern springs are hardened and designed to avoid this as much as possible.

libertyman said...

Creep is typically associated with high temperature,and yes it is dependent on the materials but I think it is an unlikely explanation for people's perceptions here.

Cincinnatus said...

I have not seen AR15/M16 magazines fail to strip a round if fully loaded. I have often seen difficulty in getting a fully loaded magazine completely seated when the bolt is forward.

John in Philly said...

I recall reading an article a very long time ago in a gun magazine about shooting some 1911 magazines that been left fully loaded for a long time.
No problems with either the magazines or the .45 ACP ammunition.

My research didn't find the original article.
But I did stumble over this article.

I don't load 30 rounds in either my GI magazines, or my Pmags, and that is for the reason that Cincinnatus covered.

Tom in NC said...

Everyone seems to be on track with my experience. A bunch of my instructors over the past recommend the downloading of one round, not the 10% figure, since all that is needed is to allow the magazine to be securely seated under a closed bolt. And for longer term storage, I load my 30 round PMags with 25 rounds, just because ...
Another magazine related tip or two - it's a good idea to keep separate mags for training, where they are likely to get beat up a bit, and have separate mags for social purposes that have been shot enough to validate their reliability but not so much that they have gotten abused. If any mags fail to feed, etc. more than two or three times, mark them as such and use them in training (malfunctions they introduce will be useful in training to clear said malfunctions). If you've used mags in a dirty, dusty environment, disassemble them and wipe them dry. Best not to use solvent to clean them, but if you feel the need to, make sure the solvent and residue if completely dried off. Do not use oil on the mag body or spring. Solvent residue can deactivate primers, and oil attracts dust and dirt which can cause magazine issues. Finally, here's one of Clint Smith's videos talking about how many mags you might think about having around. (I like the Claymore on the post behind him!)

clark myers said...

I can't argue with an engineer about what the book says. I do think the book makes some assumptions glossed over here repeating spring steel.

I prefer the video at Brownell's by Mike Watkins: Differences In Spring Rate Set Between Different Types of Spring Materials By Mike Watkins. Mr. Watkins concludes "The fact that all springs take an initial set is true and continue to do so over time as long as the same load or compression is the same."

On the other hand I draw somewhat different conclusions and my practice is not the same as our host.

In the AR pattern rifle my own practice is to effectively download but also to always load so the top cartridge is always loaded on the same side so that after loading one the new top cartridge is always on the other side. This allows me to have some idea by feel that I am pulling and inserting a normally loaded magazine and to tell by feel of the promptly ejected magazine that the top cartridge has shifted sides so I can know the former top cartridge has moved to the chamber.

This because a press check on an AR pattern firearm is dubious, hence the forward assist, and hard to accomplish in the dark. I do think ease of loading especially in an otherwise uncomfortable position is a good thing.

I also think that magazine feed lips are a more common failure point - as a magazine is used. More commonly in 1911 magazines that carry more than John Browning designed the product for, the feed lips will eventually be pounded out in use. In my experience while the spring is still doing its job by pushing the next cartridge into place vigorously.

For my own use, I expect and accept that a new in box magazine spring will start out longer than the the same spring after even very little use. I think this almost always happens regardless of number of cartridges loaded. I also expect the given magazine to take a new set and not to shorten very much if at for the rest of the magazines useful life. I accept that loading a brand new magazine to full capacity may be difficult and I expect that after being loaded and left for days or even weeks the magazine will be much easier to load and also have a remaining useful life longer than my own. Thus I have no qualms at loading a pistol magazine to full capacity and to storing a fully loaded magazine for months or years. On the other hand I also accept that some magazines, including Wilson 47D with some form of thermoplastic follower will be due for repair after a couple years of weekly use for games and high round count exercises. I think but have not tested that Chip McCormick springy followers do not have an eternal spring life. Thus my carry magazines are in a different rotation than my game/high round count exercise magazines. But it's not because I expect the magazine spring to be the failure point for a name brand magazine.

McChuck said...

I have a friend who has kept assorted rifle and pistol magazines loaded with one round less than full capacity since the 1970's and 1980's. He cleans and function checks them every presidential election year.

If you start with good quality magazines, they will last a long, long time.

Anonymous said...

I have fully loaded magazines on all regular shooters, with no feeding problems. Some mags loaded for years.
Age of weapons and mags varies greatly. Some as far back as WW one.
Am I just lucky?