Magazine Spring Fatigue: Ad Nauseam, Still No Answer

[MarcSpaz]

So, like the tile says... for decades I have heard and had conversations with people who have widely different opinions about mag spring fatigue. With the invent of the internet, I thought I would be more likely to find a real answer, but that just made it worse, since so many people claimed to be "experts" and there was no real credentials or benchmark to make such a claim.

So, what brings me to start yet another forum thread about the much discussed and ever allusive answer? I'm a glutton for debate, maybe... or just full of wishful thinking that someday I will get a real answer. So, without further ado...

I have kept 12 rounds in my 12 round pistol mag for the last year or so, daily. The only time I have not had 12 rounds in the mag was when I was dispersing rounds to unsuspecting cardboard or metal targets. After a year, I have found that the spring tension has changed slightly, but the change I noticed seem to have happened within the first week or three... and its been pretty much the same ever since.

Now, I know springs where out. Everything wears out eventually. BUT, what makes them wear? Is it sitting under compression? is it repeat compression and expansion? Is it heat from rapid expansion and compression? Just why do springs get soft?

I don't need to hear a bunch of theories from guys who read the internet once... there are enough of those out there. What would be cool to see is...

1.) is there anyone here who works with steel, makes springs, and really, truly knows the answer? (fingers crossed)

2.) have any of you ever had a feed problem that you confirmed being related to a week mag spring? If so, what are the specifics? How old was the mag? how much time did it spend under compression verses in use (spending rounds)? How much time did it spend while relaxed? etc...

3.) for guys who have been down range... how long do you leave your mags loaded? I would think at places like FOB's and during ops in hostile territories, they are loaded and ready to go for extended durations.

4.) same question for LEO's... how long are you leaving your service weapon mags loaded for? Seems like that would be all day, every day.

5.) for folks who use firearms for a living, how often do you replace your mags or mag springs?

6.) are you guys finding that you need to replace the mags for reasons other than spring fatigue?

I've seen some steel springs that were close to 80 years old (in mechanical devices) that still seemed to work just fine, then I have seen springs (like in a cars suspension) need to be replaced after only a few years. I have even seen some springs snap in the middle of a coil. I just have no real answer as to what to expect out of my mags, or any of my weapon's springs, to be honest.

Mags are cheap. Most springs in the weapons are cheap. I am not worried about replacing them from a cost prospective. I am more concerned with a mag failing to lift rounds high enough, fast enough to feed correctly during a brown fan moment. So, like everything else... just trying to plan ahead.

[trailrunner]

I don't have any solid data to answer your questions, so I won't even try to bluff. But I have a little bit of anecdotal experience. Earlier this summer, I was having trouble with one of my G17 mags. It would not reliably feed the last round. The magazine came with my gen 2 G17, which I bought around 1993, so I figured the spring had lost its springiness, and I replaced it. The old spring had some surface rust and indeed did not feel as springy as other mag springs, but the new spring did not fix the problem (I guess the only other thing to do is to replace the follower). I do NOT keep that mag loaded, and in fact, I didn't use that mag that much (I normally use some 10-rounders that I got stuck with during the 93-03 AWB). I checked some of my other old mags and found the springs had lost their springiness, so I replaced them, but I will admit that they worked just fine.

After having a failure of my slide stop spring on my relatively new G19, I'm going to start paying a bit more attention to maintenance, including replacing springs. I have 29 Glock magazines. They are numbered, and I'm going to get more regular about maintaining them, and keeping track. I don't have a schedule yet, but I'll probably replace spring and follower every three or five years. I shoot my Glocks 75 percent of the time that I shoot. For my other guns, I'll probably just make it up as I go.

[OakRidgeStars]

I don't need to hear a bunch of theories from guys who read the internet once... there are enough of those out there.

Clearly you have forgotten that this is a gun forum.

[MarcSpaz]

After having a failure of my slide stop spring on my relatively new G19, I'm going to start paying a bit more attention to maintenance, including replacing springs.

What happen there?

I don't need to hear a bunch of theories from guys who read the internet once... there are enough of those out there.

Clearly you have forgotten that this is a gun forum.

LOL... touche'

[trailrunner]

After having a failure of my slide stop spring on my relatively new G19, I'm going to start paying a bit more attention to maintenance, including replacing springs.

What happen there?

First of all, I meant slide lock spring, not slide stop spring.

About a month ago, I had only been shooting by G19 for a few minutes, when I noticed a small piece of metal on the bench. I couldn't figure out what it was, so I kept shooting another couple hundred rounds. When I was done, I left and went to my car. I was fiddling with my gear, when the slide fell off the frame. I held up my gun, and noticed a hole where the slide lock should be. Aha - that's what that small metal piece was. I went back inside the range and retrieved it. The slide lock spring on a Glock is a small cantilever spring, and mine had somehow worked its way out of its groove. I put it back in the frame, and all seemed well, but I still decided to replace it (they only cost $3). Apparently this is not an uncommon problem with G19s. For a while, the G19s had the wasp-waist spring, and those were prone to breaking, but mine didn't break: it popped out of the frame. What I also found surprising is that my gun worked fine (as long as I didn't point it down, which would cause the slide to fall off). I would have thought that the first round I fired without the slide lock would have sent the slide downrange, but as I said, I shot another couple hundred rounds without even knowing I had a problem.

[BertMacklin]

With physics of springs, you should keep in mind a few things.

1. Constant compression and decompression (loading and unloading) should wear most any spring faster than constant compression. Notice most springs, at least assembled magazines, are already under some constant compression as they are typically, when fully relaxed, longer than the space they occupy.

2. Despite #1 any compression of a spring will lead to it preferring, molding to, what ever shape its kept in. To mediate this one would limit the amount of distortion beyond its relaxed state. Ex. leaving them disassembled, assembled but unloaded, loading less rounds than the maximum, or by periodic decompression (unloading).

Evidence of these principles is far from scientific but I have still seen it. Had a 22 round G22 magazine which I have shot and altered, loaded and unload, quite frequently. I have another which I just left loaded without little adjustment at all, for quite a few months, had more spring tension, even though I have had it longer and its spent more time loaded. After noticing this decline in pressure, before any actual errors had occurred, I started taking 2 rounds out of the single stacks, and 4-5 rounds out of the double stacks I keep loaded. I change them every once in a while but not often.

Many spring failures manifest themselves first by not loading the last round. This I have seen in weapons that are really only loaded at ranges but shot quite frequently, 22.'s and such.

A final note is quality [See Post on 22/45 Magazines Failure to Load]. If its truly bad quality then lips are usually the first thing to go, long before the spring goes out, but this is really only on non-metal magazines. But a spring is only as good as whoever made it at any rate.

[M1A4ME]

Quality magazines contain quality springs. Crappy mags contain crappy springs.

Even good springs sometimes can have a weak spot and fail.

I've got M1A magazines that have been loaded for over 30 years. Only unloaded when I shoot the rifle at the range. These are surplus GI magazines, not recent/commercial manufacture.

I've got 1911 magazines that have been loaded for over 30 years. Again, only emptied when I go to the range. These are "who knows what kinds of magazines". Most are no name magazines but they are over 30 years old and there probably weren't as many "clone" manufactures or foreign manufacturers around back then.

Many of my AR15 magazines have been loaded for the last 5 or 6 years, except when I go to the range. These are a mix of mostly commercial magazines (PMags) with some GI spec (D&H and others) magazines.

The only magazines that began to fail that were obviously weak springs where some Korean Glock extended capacity magazines I bought when I bought my Glock. The time or three I used them they were fine. After a year of sitting in the case (I switched to XDMs) the extended Korean magazine springs were so weak that when I tried to unload them the spring stopped pushing rounds up after 8 or 10 came out of the magazine. I flipped the mags. upside down and shook the rounds out of them and the follower and spring "followed" the bullets downward.

[Rumson]

In a lab environment with perfect spring steel the springs will never fail. Real life though an answer is not possible due to all the variables involved.

No manufacturer has perfect spring steel every production run. It's just not possible under normal conditions. Sometimes they fail and sometimes they don't. Price generally reflects quality but perfect steel is not possible every time. I don't believe an answer exists.

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[grumpyMSG]

Springs over time do take a "set", but that will not necessarily lead to improper functioning. They can fail for various reasons, corrosion and abrasion being two of the reasons I have seen for them to fail, literally breaking. 2 short springs will not do the job of the one long spring they once were. So routinely check any of your weapon's and magazine's springs for unusual wear, corrosion and cracking. That should help avoid problems at the worst possible time. Unlike so many I do not subscribe to the just slather oil all over an AR and expect it to be good to go for a couple of hundred rounds and then slather some more on it. Just wiping the excess gunk off of it and looking at it's parts looking for cracking or damage doesn't demand it to be spotless, but it will make it easier to spot a crack here or there. As for magazines, you would be wise to mark yours as yours and in a way that you can identify one from the other, you pick a system, your initials and a number engraved or painted on them will work. I wouldn't try to stamp them (might deform the magazine) tape is a good temporary fix but if it might be swiped, peeling it off would be easy. Failures to feed could be issues with magazines could actually be one of three things, damaged lips on the magazine causing it to feed crooked, a damaged or burred follower which might not rise all the way to the top, have a corner rounded off so it binds while moving and the third, the spring which you thinking about. Certain weapons like the M249 fire at a cyclic rate that is actually able to cycle faster than a normal magazine can feed ammo. That is why using the magwell is supposed to be for emergencies. I can tell you that when it comes to AR magazines, if it is a standard aluminum body magazine and it has a black plastic follower in it, it needs to be upgraded or replaced. Magpul makes good replacements that you can pick up with springs at the same time and just make your life easier.

[jdonovan]

1.) is there anyone here who works with steel, makes springs, and really, truly knows the answer? (fingers crossed)

metal worker, hobby machinist.

Spring steels have elastic limits, both in compression, and extension. Exceed either and you will permanently distort the shape of the metal. Stay within the limits and no distortion will occur.

Based on the design of the spring, Steels chosen, thickness of wire, coil spacing, etc.. will give you a service life... # of cycles before the spring fails to meet specifications.

Generally cycling the spring from compressed to relaxed 'wears' the spring more than staying in the compressed, position.

2.) zero

Mags are cheap. Most springs in the weapons are cheap. I am not worried about replacing them from a cost prospective. I am more concerned with a mag failing to lift rounds high enough, fast enough to feed correctly during a brown fan moment. So, like everything else... just trying to plan ahead.

I've got some VERY high load/unload count mags that are still on their OEM factory spring from the 1970's. The previous owner said about 50,000 rounds went through the gun on the 6 or mags he sold with it. I've run another 10-20k through the same 6 mags. Almost all of the use has been full-auto in a MP5. 40 year old springs, 400+ cycles. Still running fine.

In the end springs are cheap. If you feel better replacing them then do it.

New front in the discussion... I've traced more bad feeding to mis-shaped feed lips than any other problem.

[MarcSpaz]

Thats all good info. I appreciate it. I don't have any reason to expect that I would have any mag feed problems at the moment. But I do keep a couple mags loaded to capacity all the time (unless being used at the range). Hearing how many decades you all are getting out of a quality mag definitely helps me feel better about it over time.

I have heard the PMAGs have more failures due to the lips being mis-shaped when compared to metal mags. I don't know if that is an "internet rumor" or not. I do have some friends that are not allowed to take PMAGs on deployments with them, only metal mags.

The PMAGs are pretty light compared to metal ones, but I have to think there is a sacrifice somewhere. I would not be surprised if the feed lips wear quicker since plastic is not as abrasion resistant as steel. Plus, I can see cracking a PMAG climbing over a wall, etc., with PMAGs in a pouch on the front of a vest or during a mild to moderate impact.

I have a good mix of PMAG and metal mags from a company called C Products Defense (or CPD). They are an American company who does nothing but manufacture magazines, and they are only $10 each. So, I figured I would try them out. So far, so good.

EDIT: man do I feel bad for folks who spent $60-$70 or more on 30 round mags during the post-Newtown scare.

[SHMIV]

Based on my knowledge of physics and my knowledge and experience concerning metal, Rumson had a pretty good reply. (I'm not discounting the more technical replies, mind you)

I fix things frequently. That's my thing, apparently. It has been my experience that man made objects break, or stop working properly, and often for no apparent reason. A chunk of steel may not want to temper properly, or a plastic part may have had some water that didn't evaporate in the pre-molding drying process ( which would cause a weak spot in the plastic)

Usually, you get what you pay for. But, sometimes, you just get the Friday part that was made by the guywho has his mind on the weekend party, or the Monday part, that was made by party guy who is now hungover. I used to work in a factory. Those guys were in every department.

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[TScottW99]

I have five magazines for my duty Glock 22. Three of them are loaded at all times. About every other month I'll unload two and load up two. Have been doing this with this weapon for 13 years now, still feeds and functions 100%.


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[Rualert]

Just my 2 cents, but I when I was actively shooting IPSC I regularly shot 1K rounds a week using the middle range McCormic mags, and some colt steel 8 rounders. Those mags shot three years of matches, and were used weekly for the 1K practice times. Only mag I ever had malfunction was a feed lip issue, and once a non name mag that had a plastic base. I keep my everyday carry gun loaded all the time, unless I'm at the range shooting it, and immediately reloading it. I also have used the standard steel 7 rounders in that same 1911 for 20 years with no issues, I do tend to buy and use the 8 round mags just for the extra round, but have had great results with either version. The no name mag whose plastic base broke, well I chalk that up to it was cheap, and lasted as expected. It was never used in a match, or as a carry mag, just because of my mistrust of it. On another note, since I own and shoot quite a few air guns, I do know that springs, specifically in the break barrel (Springers) which have a long coil spring inside a tube which slams the piston forward to compress air, and fire a pellet cannot be left cocked for days at a time, and they do take a set, and eventually break. They are considered normal wear parts. As for thinks like firing pin springs in my 1911, I tend to replace them with Wolf springs, just because they are generally a little stronger, which many consider just a slight safety advantage if the pistol is dropped on it's hammer if it happened to be down. Only other spring I have had to replace was the recoil spring on my latest 1911, but I found out the gun had been left with the slide locked back for an undetermined amount of time. Could have been years, I just don't know, and the replacement was maybe $8.00, that fixed it, and I have had no issue what so ever since. Hope my rambling helped at least a little.

Casey