High Cap Magazine Durability

[black mamba]

How long can a high capacity pistol magazine be left completely loaded without any detrimental effect to it's functioning?

I have three mags for my 16 shot Witness 9mm, and I have been unloading the mag in the pistol every week or two and loading them back into one of the other mags, so each one goes about a week loaded and then 2-3 weeks unloaded. Is this really necessary?

[CurlyQ.Howard]

From what I've read, it is harder on the springs to load and unload rather than to just leave them loaded. Take it for what it is worth as it is not my experience speaking but instead knowledge that I've gathered from this and other forums.

[Dan-O]

Like curly Q said, springs wear out with use vs. being compressed and left in that state. Regardless of which theory is correct, the fix is an easy and inexpensive one if you do wear out a mag spring.

http://www.gunsprings.com/mID19/dID100#853

[tjhands]

Not only is it unnecessary, but you're wearing the springs out faster by doing it the way you're doing it. Springs don't need "rest."

[LockedBreech]

I have stored both of my Beretta PX4 magazines loaded with 14+1 Gold Dots for over five years, only unloading to replace with fresh carry ammo or to reload them with plinking ammo at the range. They have been loaded about 99.9% of the time. The springs are still so tense that loading in the last 2-3 rounds can be a chore without an UpLula.

As has been said, your well-meaning system is tougher on the springs.

[Walt Sherrill]

This question comes up regularly, but nobody bothers to do a search. (Or they do the search, and the search function doens't do IT'S job properly...) The topic is well researched and there is a lot of internet sources available. Here's a repeat of stuff posted in earlier discussions. It starts with a quote from another shooter, repeating a point made above. Everything BELOW the embedded quote, immediately following, has been posted here before. If you follow the link included, you'll find a lot of technical evidence, provided by others, that supports the points made.

Magazine springs wear out from the action of compression and decompression (loaded and emptied, loaded and emptied) over and over many hundreds or thousands of times, not from being left loaded.

That's partly correct and partly incorrect -- using/working the springs MIGHT cause some damage over time, but in most cases, the springs have been designed to work within a range of motion, and there's enough reserve built in that it doesn't matter. (How often, over the years, have you heard about tappet springs in cars having to be replaced -- even though those springs may have cycled millions of times in a given car?)

Spring deterioration from long-term (loaded) storage while compressed is likely to be a problem ONLY with hi-cap mags used in full-size guns, or mags in compacts or sub-compacts that hold almost as many rounds as the full-size models. Some 1911s 7-round mags from WWII, kept loaded for 50 years, still work beautifully; other mags in some sub-compacts don't last long at all if you keep them loaded. Compressions or cycles alone aren't necessarily a spring killer. It all depends on the spring and how it's used.

I have had a bunch of CZs, over the years. Note: the 10-round, 15-round, 16-round, 17-18 round after-market mags used with those guns all use the same springs. Which springs, do you think, are working harder as they do their job? Do you think the spring that has lifted 17 or 18 rounds from it's compressed to uncompressed state has done the same work as that same spring in 10-round mag? Just one spring compression in both examples but a lot different work was done -- roughly 70%-80% more work, in one sense, and it's also been compressed more completely, as well.

As noted above, what the spring does (and how it does it) is as important as how often it does it. A fully-loaded mag is a working mag: it's trying to lift those rounds up the whole time it's stored away. If those springs are near their design limits, that will eventually cause some deterioration; if they're NOT near their limits, there's generally enough "reserve" left that it likely will not (ever) matter. That's why Wolff Springs recommends downloading a round or two for long-term storage of some (hi-cap and compact) loaded mags.

The life of the spring depends on what it's designed to doand how it's use pushes the spring toward the limits of that design envelope. (Spring designers talk about "elastic limits.")

Here's a link, below, to an pretty comprehensive earlier discussion, which contains links to various technical sites on the Web. It's one of many such discussions we've had here, but one of the most recent ones. One of the responders is an engineer who has taken an interest in the topic and did a lot of the research cited. Look for danez71's response.

There's a lot of bad info out there, most of it based on personal experience with one type of gun -- the experience was true for that (or those) guns, but may not be true for many other guns. Hi-cap and sub-compact mags seem to be where the biggest problems occur.

Be sure to read ALL the way through the message chain.

http://thefiringline.com/forums/showthread.php?t=521717



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[bbqbob51]

I have habit of not loading any magazine to the top. This started with my S&W 22A that when the 10 cap. magazine was loaded with 10 rounds the second shot would stovepipe about 50% of the time. When loaded with 9 rounds, it performed flawlessly. I figured it had to do with the magazine spring being fully compressed at full capacity. My 9mm Beretta Cougar, which is my primary house gun, has high capacity 15 round magazines and I load it with 12 rounds to avoid the full compression. I don't need no stinkin' stovepipes in a self defense situation!
The owner of my favorite gun shop claims that leaving magazines loaded with the springs compressed for a long period of time can cause spring failure. He says he has seen it happen numerous times in the past 30 years. I'm not 100% sure if he is correct but just in case he is I took his advise and take the gun out at least once a month to decompress the spring by shooting it.

[NWCP]

You're better off leaving the mag loaded for a longer period time. It's less wear on the spring than constant loading and unloading.

[Walt Sherrill]

You're better off leaving the mag loaded for a longer period time. It's less wear on the spring than constant loading and unloading.

There's another message chain currently active on mag springs -- with a lot of technical points and illustrations. It's come back to life since this message chain began -- and it's cited above. New info has been added.

What you write, above, could be true with some mags, and totally false with others -- depending on the mag, it's capacity, and how the gun designers intended the springs to be used.

Leaving a 7-round 1911 mag fully loaded will probably have no effect on mag performance over decades. Leaving a 7-round sub-compact mag fully loaded over a year's time may lead to the rapid decline of that gun's mag springs. Loading or unloading a 7-round 1911 mag will probably have no noticeable effect on the life of the mag/spring. All springs were not created equal, and gun designs ask different things of the springs used in their designs. This is true of recoil springs and mag springs in particular.

(It's not just leaving them compressed that causes deterioration, but how much they are compressed in actual use. As noted in the other message chain cited above, some of the ultra compact guns, like the Rorhbaugh, the designers recommend replacing the recoil springs after just a few hundred rounds...)

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[thedudeabides]

I was given an FNH Hi-Power that was bought new, loaded, and the mags had remained that way almost as long as I had been alive on this earth.

They still work just fine.

[Walt Sherrill]

I was given an FNH Hi-Power that was bought new, loaded, and the mags had remained that way almost as long as I had been alive on this earth.

I don't think I've heard of many 13-round BHP mags failing, either. But, as noted elsewhere, the magazine springs in a 13-round BHP mag aren't pushed to anywhere near their elastic limit. Other guns using mags of essentially the same size mag body, stuff up to 18 rounds in an equivalent space. The springs seem similar. Which springs do you think are being used harder?

I have a marvelous, old T-series BHP and have tried a variety of different mags for it, over the years. I've had a bunch of new 15-round BHP mags from South Africa that failed relatively quickly, and most of them weren't stored loaded -- they just died. Never had problems with Mec-Gar 15 rounders, however, but I don't store them loaded.

I also have a 30-round BHP mag, somewhere, that I've never tried, <Grin> I received that in a box of BHP mags I picked up cheaply, but I can't figure out a good use for it, unless a monopod is called for. I suspect finding a replacement spring will be a problem.

[Skans]

How long can a high capacity pistol magazine be left completely loaded without any detrimental effect to it's functioning?

Any good factory magazine will last at least 20 years. I have a Glock 17 that I have been using the same magazine in for over 20 years - keep it loaded when its stored, and it still functions flawlessly.

I found an old Polytech AK magazine that I had stored fully loaded for over 20 years - nothing wrong with that one either. My 15 round magazine on my EAA Stock 10mm is usually loaded when stored (too lazy to unload it after use), and it functions flawlessly.

Keeping any (good) magazine loaded with the spring compressed won't affect it at all. Many will tell you that the spring wears out by repeatedly compressing/decompressing it. However, my experience has been that I have never, NEVER worn out a factory magazine from use or from storage. As to cheap aftermarket magazines, I will have to adjust the feed lips every now and then because they will distort - usually due to thin steel or a lack of heat treating (but the springs still work fine)....I really should retire those magazines to the waste bin.

[Dragline45]

Springs aside, has anyone seen the actual magazine body or feed lips break, wear, or fail over time from being kept loaded over many years?

The reason I ask is since I live in Massachusetts and I can only have pre-ban high capacity mags I cant just hop on the internet and order more if they break. I have a few pre-ban factory Beretta 92 15rd mags that when I got were brand new and never been used, I also have a few pre-ban USGI 20rd M14 mags which are also in excellent shape. I keep them loaded at all times but never use them at the range except for the initial function testing since I don't want to wear them out, so for range use I just use the factory issued 10rd mags. Has anyone experienced magazine feed lips being distorted over time from being kept loaded? Also can I reasonably expect these mags to last my lifetime seeing as they don't get used except sitting loaded in the guns and in the safe.

I feel like since they are constructed of quality steel they should be fine especially since they don't see much use at all. I also have spare mag springs, followers, and floor plates put aside just in case. I know this sounds like a dumb question but I never heard or read anything on it.

[Walt Sherrill]

The only time I've seen magazine feed lips fail is when I've picked up or been given some cheap after-market (or fake/knock-off) mags.

Most factory mags are high quality, and a good many of them are made by Mec-Gar, the "gold standard" of the gun magazine business.