spring degradation in loaded magazines controversy - American Rifleman

fletcher said:

We recently discussed the issue, with a definitive (i.e. scientific and observed) conclusion in this thread.

To address this article, it is not entirely correct on two points:

1) Most of the compression, as a portion of the total potential loss, is lost short-term (i.e. a few hours). For example, leaving it loaded 6 months would really be no different than leaving it loaded 6 years. There could, of course, be exceptions. The solution would be to get a spring designed such that there is no significant loss if the magazine will be left loaded for an extended period.
2) Loss of compression is dependent on many factors, so the exact time would have to be determined experimentally for a particular spring design. Not impossible to determine, but it would be a hassle.

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My thread got quoted. Cool.

beatledog7 said:

Cynicism pumps to full...

If I sold mag springs, I'd easily convince myself that all mag springs should be switched out at least annually then preach that to my potential customers. Ka-CHING!!

Cynicism pumps to idle...

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No doubt.

However, if you were in the spring business, you'd probably want to avoid having your customers experience preventable failures due to weakening springs, and then looking elsewhere for their next springs.

Rock & hard spot, right?

BTW, I can't remember the specific numbers anymore, but back when the feds were first using some well known company's 8-rd 1911 mags, based upon what they reportedly observed (in range evaluations?) observed they recommended their agents replace mag springs either every 2,000 or 2,500 rounds fired, or every 6 months (left fully loaded), whichever occurred first. They were apparently serious about trying to avoid unnecessary functioning issues. Dunno what they're doing nowadays, or which company's mag(S) they're using.

I've seen 9mm mags left fully loaded work reliably for years .. and then I've seen another type/brand of .40 mag start to exhibit problems obviously related to weakened springs in as little as 3-4 years (duty guns). I've had another S&W armorer complain that his agency wouldn't let him spend the money to respring 4006's at the 5 years-of-service point (recommended by S&W, unless 5,000 rounds are fired first) ... and then later tell me how at the 7-year point a LOT of their duty mags started to exhibit weak springs and produce lots of stoppages on the qual range.

I've heard different things in different armorer classes over the years (more than 20 classes). Take your pick. One consistent recommendation is to periodically check the springs in any particular guns and mags to confirm normal tension & functioning ... to make sure the gun & mag(s) will run when really needed.

Prudent.

That old risk management saying, "Predictable is Preventable", has some merit at times.

I have had AR magazines fail after being compressed for too long. However I chalk those failures up to sand getting in the spring and wreaking havoc on the motion of it. Thankfully it never put my life in jeopardy. Given dry, high quality spring metal, and low air particulate (dust, dirt etc) there should not be a noticeable weakness in springs left compressed. My ex's grandfather has kept an AMT backup under a kitchen cabinet at his hunting/fishing ranch for almost 25 years. Still fires just fine without rotating out the mag or ammo.

I have a 1903 Colt that has always been loaded. From Grandfather to Father to me, still runs fine.

Metallurgy 101: A loaded mag that stays loaded will not loses strength, and an unloaded mag will not lose strength. It is the constant loading and unloading that wears your springs out, that's ther character of spring steel. Trust me I work with heat treating and machining all the time.

If you tear down a lot of old automotive engines that have set for years, you will find that the valve springs that were in the compressed state when the engine stopped running and was left to sit, will be shorter in free length than the ones that weren't. If you test them for spring rate, lbs-per-inch, they will still all be the same stiffness. The ones that were left compressed will just be shorter in uncompressed length.

How far a spring is compressed into to elastic range can be/is just as important as the number of cycles.


If only the number of cycles a spring sees is the sole contributor to degradation then threads about replacing recoil springs would out number threads replacing mag spring at least 10:1.


Its just that simple.

R.W.Dale said:

Sigh

Take a look outside in your driveway

See that $40k piece of high technology machinery. Its sitting on four springs that are holding up its entire weight.

THEY WILL NOT wear out from sitting in the driveway nor will the dozen or so valve springs that are sitting over open valves at rest for however long the vehicle sits.




posted via that mobile app with the sig lines everyone complaints about

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I've had MANY cars that had the suspension springs sag in as little as 7-8 years. It's not as common today but it's a known phenomenon. Trust me, if a spring and the system that confines and controls the spring are designed so that the spring approaches the yield strength of the material in normal use that spring will take a set and also weaken whether it's cycled or not.

Take a look outside in your driveway

See that $40k piece of high technology machinery. Its sitting on four springs that are holding up its entire weight.

THEY WILL NOT wear out from sitting in the driveway nor will the dozen or so valve springs that are sitting over open valves at rest for however long the vehicle sits.

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Valve springs are compressed around no more than about 1/2" and the spring itself is around 2" or maybe more.

So we're talking that its compressed only roughly 25% of its length.

Mag springs are compressed substantially more than that.


An engine turning 2000 RPM's for just 1 hour compresses the valve spring 120,000 times.

Ive got well over 3000 hrs on my truck motor. Each valve spring has seen well over 360 million compression cycles.

By that analogy, a 10 round mag spring should last 3.6 billion rounds over 10 years while being stored fully loaded over each night and still be going strong.


I'm going to hold firm that there's more to it than just compression cycles that degrades springs.

I've had a fully loaded magazine in my PT-92 since 1990, granted I take it out and shoot it regularly.
Like some have said, I think the magazine springs have lost some of their tension but not enough to cause an issue.
I'm from the school of "if it ain't broke, don't fix it".

In my opinion the biggest problem with the great spring debate is that most people seem to base their theory on spring life on a false assumption - that all springs are made of the same material and they all recieve the same tempering. They're not and they don't. The world just isn't that simple. I also feel that it is a mistake to compare a magazine spring to something like a valve spring or a suspension spring. While you could "overbuild" a magazine spring out of very heavy gauge wire and it would last forever unfortunately you would never be able to load such a magazine.

Mag springs are compressed substantially more than that.

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Even "empty" they are compressed.

Many myths and ledgends are based on things that used to be true. For hundreds of years springs were made in blacksmith shops by people who did not have the level of technology that spring makers do now.
Besides, if you really think about it most of the springs in modern guns are under some level of compression all the time.

Sorry to the guy who wrote into American Rifleman, but that's not how springs work. Springs degrade by metal fatigue. Metal fatigue is induced by adding and removing load from the spring, making it do work. Being held compressed or free does nothing. You can theoretically keep a mag fully loaded for years, and the resulting work done on the spring would only cause the same amount of stress as if it had been loaded up and then dumped a few minutes later. Now on the other hand, this isn't at all related to what happens to magazines which are mistreated and damaged by external forces.

I have two mags for my home protection Beretta M96 loaded for several years and after this Rifelman article I decided to check things out.
Waste of time!
A spring, is a spring,is a spring,is a spring!

Only if it is a crappy spring being used beyond design limits.

My experience with two extremes:

I kept magazines for a Ruger P95 fully-loaded for many years back when one was the only gun I owned and cared to own (this was before I got more into firearms and was also ingnorant that mag springs could weaken) and the springs continued to function fine thru many years of constant compression and occasional use at the range.

My friend bought a Springfield Armory XD-9 back in 2002 or so and it came with the ten round Klinton mags. Not really a gun guy like me, he went shooting with me once to fire it and afterwards went home and loaded it up with hollow points for home defense. A year later we went shooting again and his magazines were consistently failing to feed the last round.

I think it depends upon the quality of the spring more than anything else.

The better the quality of spring, the longer it takes for the spring to weaken. I don't see how making a better spring makes it impervious from degrading

This:

The better the quality of spring, the longer it takes for the spring to weaken.

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Car springs are under constant compression and decompression and how often has anyone had to change them?
I had a .22LR Squires Bingham mag spring wear out after less than 500 rounds and I have had high quality pistol mags from various manufacturers last many 1000's of rounds with no noticeable deterioration.

Take a look outside in your driveway

See that $40k piece of high technology machinery. Its sitting on four springs that are holding up its entire weight.

THEY WILL NOT wear out from sitting in the driveway nor will the dozen or so valve springs that are sitting over open valves at rest for however long the vehicle sits.

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I would consider the truck just setting there empty to be the unloaded state. Throw 1000 lbs of brick in the bed of your half ton pick up, leave them for a couple years, and then tell me that keeping a spring loaded doesn't weaken it.

Freightcars are loaded a great portion of the time. Wonder how those do.

I know I already posted in this thread, but I want to say one more thing, I worked in the automotive industry for 40 + years & I have seen countless overloaded springs come to failure.............

I can give you my nephews # and he could tell ya, he`s changing springs out on box cars all the time.................

I never had a spring in a mag wear out, in over 4 decades of pistol shooting. Either I am very lucky, or they just don't wear out unless something very unusual happens.
This has been discussed so many times with no conclusive evidence that under normal conditions this ever happens, that I really don't think about it.