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Magazine spring madness: 'creep' to your 'elastic limit' to un-earth the urban legend of 'spring-set'
American Handgunner
May-June, 2003
by John S. Layman
http://www.findarticles.com/p/articles/mi_m0BTT/is_163_27/ai_99130369

The shooting sports are full of some of the most knowledgeable and capable people you'll meet anywhere. I've been impressed consistently with the abilities of those I meet at the range to diagnose and fix a gun problem with as little as some spray lube and a cotton swab. However, sometimes a myth will creep into the folklore.

The magazine spring myth has been around for many years and is growing in popularity. It goes something like this: "You should unload your magazines when they're not in use or the spring will weaken causing failures to feed." This has gone as far as shooting competitors actually unloading their magazines between stages to extend the life of their springs. A variant of this myth is: "You should never load a magazine to capacity and should always leave it one round short." What if you need that round some day?

Recently, I read an article in a gun magazine suggesting you rotate your magazines so the ones not in use can "recover and rest." The same author uses the phrase "spring-set" to describe weakness of a spring because it was compressed for a long time. Hogwash. There's nothing further from the truth. Springs don't care how long they're compressed and don't require rest, recreation or even a vacation from time to time.

Shameful Spring Benders

To put this one to rest, you have to understand creep. Creep is the slow flow of a non-ferric metal like copper, brass and lead under force. At temperatures outside of a furnace, steel doesn't have any appreciable creep. Under most conditions, steel flexes and then returns to its original shape. When pushed past its elastic limit, steel will bend and not return to its original shape. All designers of well-made magazines make sure the spring never approaches the elastic limit when the magazine is fully loaded. Honest. This means the spring will not weaken when the magazine is fully loaded -- not even over an extended time. Like 50 years. American Handgunner recently ran a story about a magazine full of .45 ACP that had been sitting since WWII and it ran just fine on the first try. So there you go.

Now that the light of truth is leaking out, lets talk about what is causing failures to feed. The only way to weaken a magazine spring is to flex it past its normal range (elastic limit). If this is happening, somebody is trying to overload a magazine or has "adjusted" it by bending the spring. Both of these could cause feed failures. Shame on you if you're a spring bender.

Carlton Nether, Customer Service for Beretta USA, tells us keeping a pistol magazine loaded for an extended period doesn't cause magazine spring failure, however, failures to feed can result. He says, "The ammo will 'roll' in the magazine. If the mags are kept loaded and moved around a lot -- say on a cop's belt -- the rolling action can, over time, cause creases in the cases. These creases can cause malfunctions. Also the top bullet will roll against the magazine lips and creasing can occur there as well. Just check old ammo that's been bouncing around in a magazine for a long time.

We tell police officers if they keep loaded magazines, take a few seconds to "cycle" the ammo. Periodically unload the mag and reload it in a different sequence. This movement will allow the bullets to be in different parts of the magazine and help eliminate creasing.

At STI, Dave Skinner, President and CEO says, "Personally, I rotate my 'under the bed' and 'under the seat' mags about every six months. I always empty them the 'fun' way and have never had a failure." Given what we learned above, this sounds like a good idea. Smith and Wesson customer service also says magazines can stay loaded indefinitely without hurting the spring.

As we add force onto a spring, it will displace the same amount for each amount of force we add. This is true until the spring passes a certain point called the elastic limit. Robert Hooke discovered this theory back in 1660. Hooke's Law states: "If the applied forces on a body are not too large, the deformations resulting are directly proportional to the forces producing them." Which means, in actual human being language, if we load a spring past its elastic limit, it permanently deforms. It still provides a force against the load but the force is no longer proportional. If this happens, when we unload the spring (such as when we empty a magazine that has been over-loaded) the spring never returns to a state where it can provide the same load for the same amount of displacement.

Trust Us

When a magazine manufacturer designs a spring, they plan for a preload. The spring is already compressed some in the magazine. On the curve below, this would be Point A. The spring compression would be designed to be below the Elastic Limit. When fully compressed, the spring would be at Point B. If the spring is ever compressed past the elastic limit, say to Point C, it won't ever behave the same. Like a recalcitrant lazy Uncle, it will have a lower spring force for each amount of displacement. On the drawing, the spring would now cycle between points D and E. This means that -- particularly with the last bullet or two -- the force pushing the bullet up would be less and lo-and-behold, a mis-feed might occur.

When somebody stretches your spring to "fix" your magazine, they are trying to get you back on the original curve. They may get pretty close, however, it's unlikely the spring will ever perform to its original design. The elastic limit is now shifted lower and your magazine spring may fail to perform fairly quickly.

Having said all this, if you have a magazine that isn't feeding right, what should you do? First, disassemble the magazine and clean it thoroughly. Then try it with new, factory ammunition in a freshly cleaned gun. This takes away some of the possible causes. If you are still having feed problems, send it back. Even the low cost, after-market magazine manufacturers will fix the problem at no cost to you other than shipping. If it's a magazine from the gun's manufacturer, let them troubleshoot and repair the problem. Otherwise, toss the mag. It's not worth risking your life to save a few bucks. And that's the truth.

RELATED ARTICLE: Definitions

Creep: The flow or plastic deformation of metals held for long periods of time at stresses lower than the normal yield strength.

Elastic Limit: The maximum stress that material will stand before permanent deformation occurs.

Yield Strength: The stress at which the metal changes from elastic to plastic in behavior, i.e., takes a permanent set.

Permanent Set: Non-elastic or plastic, deformation of metal under stress, after passing the elastic limit.

Magazine Recommendations

* Clean your magazines when they get gritty. Apply oil then remove all excess. Oil attracts dirt that may cause malfunction.

* If you find rust on the spring, this is culprit. Rust changes the thickness of the metal and reduces the force applied to the follower. Cleaning off the rust may help. For a gun you depend on, replace the spring. All the major brands and most of the smaller ones have replacement mag springs available or try Wolff Springs.

* If you keep a magazine loaded for long periods, rotate the rounds every few months. If you carry a pistol on the job or in your car, cycle the ammo frequently. These actions prevent creases from forming which may cause a misfeed.

* If you experience feed problems, first clean your magazines and weapon. Fire a couple magazines of new factory ammo to see if this resolves the problem. If not send the magazine back to the manufacturer -- or toss it.
 

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Good article JT - it is time the myth was dispelled, or at least explained!

Cleanliness with mags far outweighs any concerns over spring fatigue.

I often remind folks of a valve spring in an auto - that sits at full compression for maybe weeks and yet will once more s]close its associated valve just fine when run.

Only thing that could feature is actual poor spring material selection and bad heat treatment - get those right and it's good for almost eternity - corrosion permitting.
 

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Discussion Starter #3
Good point about the valve spring in an auto.
 

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yep ive never worried about it valve springs same thing unless you own a ford ... if my mag springs were made by ford i would change um
 

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Ewwww

Good read...

Bud White said:
yep ive never worried about it valve springs same thing unless you own a ford ... if my mag springs were made by ford i would change um
What's this? A mod trolling for Ford fans? :p I'm sure there's some Ford fans around that would think those was fightin' words!

(I agree with you, just thought it was funny!)
 

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Bud White said:
yep ive never worried about it valve springs same thing unless you own a ford ... if my mag springs were made by ford i would change um
:haha:
 

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just stating the Facts how many fords have you heard about dropping valves due to springs breaking VS any other model
 

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I admit it, I grew up believing that you would wear springs out unless you loaded one less round.

I grew up believing that a 30 round rifle magazine should only be loaded to 25 rounds or it would malfunction every time.

I believed that springs wore out if left under tension forever. It took me years to let that one go. It's so counter intuitive.

I think at one point, there was a grain of truth in all of these beliefs when the technology was less refined.

And I think if you have an old or just plain finicky gun anything is possible. But 99% of any kind of typical, decent quality or even not so decent quality magazines are going to work like they're supposed to.

The XD magazines will make a believer out of anyone that you can leave a magazine loaded forever and it not lose any tension. Do you know why my carry mags are my carry mags? They're the only ones that are broken in. Dear Lord these things are tight. I keep meaning to load them all up and leave them sit that way for 6 months to break them in, but I can't...
 

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Glock Mags are like that too Euc you good till round 15 on my 9mm cramming the last 2 in is hard same on 10mm good till round 13 then..

only Glock mags i have i can load all 17 9mm in are 2 first gen mags i bought used
 

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This reminds me of my three SIG 10 rounders - two have a ''9'' in Sharpie on them, because unless I work real hard - getting #10 in is hell! 15's are Ok and so are 20's but those 10's - reminds me - must load 'em up full again to leave em sit!
 
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