I've been going over these threads.  Ever so often someone has a compelling reason why one choice is better than the other for whatever reason.

AR mags in long term storage to be kept loaded or empty?
(I expect the storage period to be greater than 50 years)

Poll inbound

Loaded will not hurt anything.

Still, I downloaded ~ half as it seemed obscene to have that many loaded.

I settled on a number to keep loaded for grab and go, another regarding range mags that I rotate through (I hate spending range time thumbing rounds), and store the rest for "someday".

Personal preference at best.

Depends how many mags you have and how often you shoot.

I'd guess I have 50 mags and half loaded with 28-29 rnd.
I have a home range, go out and shoot 3 mags then put them in the needs reloaded stack.
Same with other guns. Then I will reload them all at once or have my son do it.

I have loadout and defense/range mags loaded. More than I could shoot in any situation. I also have many new mags still in wrappers stored long term. I know this don't help OP.  

Full. Saves space instead of storing both ammo and magazines separately. Also makes them ready to use.

All I have read over the years is Compressed springs and at rest springs (empty mag.) do not loose tension. It is the repetition of loading and unloading that weekends the spring. I have found some of my Dads M1 Carbine mags loaded, shot them empty and was going to change spring due to age. The old spring was as good as the NOS one I was going to replace it with. Have had to replace som 20 rd AR mags from Vietnam that have seen much use. Same with pistol mags.

Always have a significant quantity of Ready Reserve (loaded) mags to grab & GO!

But for 50 years of storage I'd keep those empty & ammo stored separately air tight & desiccant packed.

Bigger_Hammer

I keep about 20 loaded. I could load more, but I dont due to lack of effort. Honestly, if 20 loaded mags won't get it done, I'm probably dead.

Both.  Poll is missing best choice/option

There are major nuances to this subject.  Maximally-stressed music-wire springs absolutely do experience time-dependent stress relaxation (due to loss of free length) at room temperature.  It is logarithmic decay - most of the loss of length occurs in days, weeks, months - the rate of loss is continuously decreasing, because the stress that is driving it is continuously decreasing.  You're never going to pull out a completely flaccid spring from a mag that was loaded from WWII.

17-7PH is basically impervious to this, at room temp, and I don't think that the AR magazine spring is operating beyond its yield strength (it isn't maximally-stressed, at least, I don't think it is).  Chrome-silicon is somewhere in between music wire and 17-7PH.

You'll never fire enough rounds through a single magazine to even begin to test the spring from a fatigue standpoint.  If you fire 6,000rds out of a single 30rd mag, you've only cycled it 200 times.  That is essentially zero cycles, from a fatigue standpoint.  You can cycle a magazine 2,000 times with a wooden dowel  and then shoot it, it will likely not be degraded in any way.

Funny story I've been trying for a year or so to make a machine that just cycles a mag and keeps count.

That's called a "gymnasticator."  Yes, it's a real thing.  When I first heard about it, I thought the guy who told me about it was bullshitting me.

I looked at the M1 Carbine Magazine Spring drawing before I left the house (that TDP is available from Nicolaus Associates) and there is a note that says "DO NOT GYMNASTICATE."

I've had AK mag springs take a set, but never AR mags.  I have dozens that stay loaded with 28 rounds indefinitely.  If I shoot some I reload them before storing.

I'm not saying that an AR mag spring will not take a set, just I haven't experienced it.

+1

I've got loaded mags for SHTF grab n go plus some loaded for the range...

...all the rest are not loaded (these are for long term storage, passing to my kids/grandkids etc...)

Do what you like, but in general I don't.  A number of reasons; feel free to shoot them down.

1) I don't live in a setting where I need to grab a rifle and thousands of rounds of ammo pre-loaded onto magazines, avaliable on instant notice.  Kyle Rittenhouse fired 8 rounds.  You should have 1 or 2, or even one full range outing preloaded, and that's about all the benefit you'll likely ever get.

2) yes, in theory pre-loading a magazine causes no wear on the spring.  ... in theory.  That would be for a perfect metallurgy spring stored in perfect conditions.  In the real world, your magazine will have some degree of temperature cycle and associated thermal expansion every day.  Vibrations such as from handling it, or just the fact there is more vibration in the world than you might think, results in micro-cycling that spring a little bit all the time.  Micro-cycling that spring while under full tension, is going to have a notably great wear and weakening effective over time, than one that isn't tensioned.  Yes, lots of guys have loaded mags they run decades later just fine.  "Just fine" doesn't mean that spring is still at the same actual tension and remaining life, as if it would be if left uncompressed that time - it just means it still working right now, "just fine".

3) There's an assumption that high force acting on feed lips has no effect.   See item 2.

4) Ammunition tracking.  I know people who just jam full their mags with whatever.  Hey, what's this ammo, are those the 77's I made you, or are they the 55 HPBTs?   Sometimes you can tell anyway, sometimes not.  Preloaded mags not clearly marked with what's in them, becomes a mystery mag of ammo.  I don't like shooting mystery ammo.  Over my 2 decades here, it seems a disproportional number of "my gun blew up" posts, tend to involve mystery ammo so handled.

5) ammunition tracking part II:  
Ammunition Recall Notice






Hmm... what ammo and what lot is in what mag?

6) I don't always know what gun and what ammo I feel like shooting that day.

7) Some ranges have capacity limits.  One of mine does.  I cannot load more than 5 rounds in a magazine at a time (due some range incident, related to a runaway gun, I guess).  Sure does suck showing up and having to strip out 25 rounds.


Or to summarize, it locks in you in a setting and configuration with ammunition and quantity that might not actually be what you want or need when you finally get to it; and makes it harder to track just what you have where, at the reality of yes - accelerating spring wear, at least some.

I keep 10 loaded at all times, and the rest are unloaded.

I'm in the "both" camp.

I keep 3 loaded.  The rest are stored empty.  It takes no time at all to load magazines provided your rounds are on stripper clips and you have spoons or a strip lula.  I have no doubt that my stored, empty, aluminum magazines will work decades from now.

My range stash is loaded and stored in cans and then the fresh stash I have accumulated to draw from to replace damaged ones are always empty until they enter the range rotation, same as all my magazine fed firearms. I keep enough AR mags loaded for 2-3 average volume range trips at all times so I can grab and go when the mood hits Me and never reload on the range.

I reload them at my leisure at home when I'm bored and I feel like it, sometimes just one or two here and there. I have seen enough educated takes about it harming nothing to figure why not do it. The only AR mags I have had to junk in a few years of doing this were one or two metal ones that fell off a tall safe loaded and got bent feed lips.

Thats the most fudd thing I've ever heard.

Oh you nailed it. That's only on page one of the FUDDness.  At times im curious why they don't have a Flanned Only, dress code.
Logic is if a gun goes runaway, only 5 rounds are at risk. I guess so, but am not aware of this actually being a big problem.

I have a mix.  

Loaded mags in gear, more loaded for storage.  More than I would need for any kind of situation.

Have some range mags that are unloaded so I can only put in what is needed for a course of fire or drill.

Have still more that are unloaded, new in the wrapper.

I keep about 70 loaded and about that many more NIW.

I don’t believe you.

That is a really cool test and post.  

Basically, it really doesn't matter.   I would have thought something measurable would show up, but they gave this a pretty good test.  This is actually kind of one of the better tests on the topic I think I've ever seen.  Obviously you can't do a 20 year test, unless you wait 20 years, but it was a pretty high rigor 1 year test with a lot of replicates and a pretty good test plan.  I liked it.

Here's their data-dump.  

https://static-cdn.ammunitiontogo.com/media/files/AmmoToGo

I keep a few loaded and the rest unloaded.

I've kept some Glock 33rd 9mm mags loaded for a year, after scragging them 10x, and noted that the springs lost about .400" in length - completely unsurprising for music wire.  They felt exceptionally weak at the top, but I did not fire them. I reloaded them, and will check them again in a year.  I also have some 12rd and 17rd mags that I scragged and then fully loaded, and will check them at a certain time interval.  I suspect the Wolff springs in the 17rd mags are chrome-silicon, but I don't know that.

Note that I am not saying that the springs would cause a malfunction - maybe they would, maybe they wouldn't.  I'm only noting that maximally-stressed music wire experiences a time-dependent loss of free length in a depressingly-short period of time (weeks or months).

I'm not sure that I would bother testing 17-7ph springs for creep or stress relaxation.  I don't think you would ever be able detect any at atmospheric temperatures.

ASM Metals Handbook Volumes 1 and 8 have stress relaxation data and stress relaxation testing procedures for springs.  It's pretty interesting.

I kin show ye.


Fer a fee.  

This is easy.  Rig up a magazine under your car so every time you hit a bump, it cycles your spring.  And get you one of those clicker counters that starts at 0000 and counts up every time you press the button.  Zip tie that such that when your magazine compresses, it presses the button.  Then just drive around normally and periodically peek under the car at your counter.  

As far as the poll goes, I'm in the "both" category.  You have to load up your rounds into mags before you can shoot them.  May as well do it while you're sitting on your butt watching TV.  I try to keep enough mags loaded up that I can go to the range a few times and not have to load any.  I keep some other mags still unused in a box, still in the wrappers and such.  I dont need them open and loaded right now.  I have plenty of other ones in my rotation.  I keep some of them new and pristine.  One day magpul may decide to stop making X color or okay may stop making X magazine.  I may decide to sell or trade some off and they are worth more unopened.

Stripper clips and feeder spoons!

Have a grab and go can with 840 rounds in mags. Keep an empty box with lot info in the can. Half magpul with covers, half GI with magpul followers.
Yes the GI mags have 28. That’s the way I was taught a long time ago.

If you keep magazines loaded ready to be used in emergencies, I like keeping them in the Savior brand pouch holder. 6 magazines 3 per side and well protected. Ditch the cheap strap they come with and find something better. I have some old laptop cases and those straps are great. I keep everything loaded except some range magazines.

FIFY

I have loose mags and new mags.
I haven't bothered opening any new mags for several years.

Here's a guy that did a test of mags that were loaded for 18 years.  Not perfectly scientific, but makes you think:

That's how I do it

Apocalypto is deceased, FYI.

An empty magazine is worthless.

All mags loaded all the time.

As posted above, an empty magazine is worthless, they don't even make a good paper weight.

If there is one thing I cannot stand, it is having to load mags on the range......I ABSOLUTELY WILL NOT DO IT!!!

Every magazine purchased (rifle and pistol), gets inspected for dents (the metal ones), cycled with a dowel several times then immediately loaded full and put in a marked can.

Every gun has a full mag in it, then I have about a dozen or so extras I keep loaded.  The rest stay empty.  When I go to the range to test ammo I don't want to have to unload magazines to load with 3-5 rounds that I'm sighting in and/or testing for accuracy.  Not to mention I'd probably forget what mags were loaded with certain ammo.  Also a lot of the ballistic tip & soft point lead bullets can get dinged up when you are rearranging, moving or just looking for something.

Never understood why people load every mag they own.  I have 6 mags I take to the range already loaded.

Both.

24 mags in a FAT50 loaded and ready to go.

All the rest empty.

Wait, what?

@3-gun

He passed away from cancer a couple months ago, sadly.

I download by 2 rounds and keep a basic load in pouches on my belt, on a plate carrier, and on a chest rig so I have multiple options. My go bag with SBR AR has another half dozen loaded mags. Then I have a range bag with around 20 loaded mags.

This all really translates well to range use. I am not concerned about shtf to any real degree, though my range storage and load out lends well to an unforeseen incident.

All other 300+ mags are stored unloaded to prevent the feed lips from spreading. Yeah I know pmags have top covers. I have a mix of USGI aluminum and Pmags. I prefer to keep my spares new. Ammo is stored in ammo cans. Mags are stored in big plastic totes.

you won't live long enough to be able to know if storing them loaded will affect their life.


I would suspect that the storage conditions have more of an effect than just time (ie heat & humidity or moisture)

Both are acceptable, and neither causes more wear and tear; quality springs wear out from cycling, not from being stored in either state. I vote for full, because empty mags are useless.

I stored my mags loaded. Some for years without using them. Never a problem