Rotate mags?

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I was looking at a web page to buy a couple extra mags and saw this

Grab a few spare magazines for your Bodyguard today, and don't forget to rotate your carry/loaded magazines every 3-6 months to ensure maximum reliability.

Please explain why?
 
Guys, I've made and dealt with too many springs and have some for a few weapons that have been continuously loaded for over 40 years straight.

They don't fatigue any more than the springs on the valves or suspension do- a rarity indeed and very often needlessly replaced.

Let people produce all these "fatigued" springs for analysis.
 
I rotate my mags but only because I want to make sure they are all functioning normal
 
Fifteen years of daily carry with the M9 Beretta at "work." At the start of shift, we arm and load one in the chamber. At the end of shift, we de-arm and the round that was in the chamber goes back in the magazine.

Keeping a magazine completely loaded will not weaken the spring. The "remove round(s), add round(s)" is what weakens it. At one point many years ago, the gov't issued 15rd magazines that had been subject to 20 years of such behavior daily would quit feeding after about 5 rounds due to spring fatigue.
 
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I've had certain mags loaded for over 10 years without being touched, (30 rd AR mags with 28 rounds loaded) and they were 100% reliable when I emptied them at the range recently.

I can definitely see wkcars point about rotating them to make sure they all function properly. I had a couple of 9mm Hi Power mags that split along a vertical weld on the back side of the magazine body, and I might not have caught them if I wasn't rotating mags regularly.

One thing I should point out about repeatedly chambering/de-chambering rounds and replacing them in the magazine is that you need to be careful about bullet setback. I've only had it happen once that I noticed, but that's because the bullet setback was really significant. It was in a .45 cal Sig P220. I might not notice if the bullet gets pushed deeper into the case by one or two thousandths, but the one time I caught it was when the bullet setback was a little more than .1". That's pretty huge, and I'm glad I destroyed that round rather than trying to fire it.
 
In defense, there needs to be a qualifier.

A properly constructed spring for the load will not suffer fatigue or set.

Where a lot of these "alleged" problems come from is not a spring malfunction per se but spring "binding" either from a slight dimensional issue or rough spots.

Combine that with the gummy residue with oil and dirt and you can get magazines that hang up giving the "illusion" of spring fatigue but not really.
 
Funny, I found a fully loaded SIG P226 mag that had been in storage for more than 10 years (likely closer to 15) in a sealed bag and the spring was markedly weaker than the others that I had. It could be a one-off, but I am skeptical.
 
Originally Posted by 2015_PSD
Funny, I found a fully loaded SIG P226 mag that had been in storage for more than 10 years (likely closer to 15) in a sealed bag and the spring was markedly weaker than the others that I had. It could be a one-off, but I am skeptical.


That's probably not a concern but your skepticism is well warranted.

I do enough NDT on springs in mining and conveyors and the failure modes are basically the same and here's how it goes.

Starting with a properly engineered and built spring ( proper alloy, wire size, dimension and geometry with heat treat and plating if desired)……

The spring will eventually fade and fail due to cyclic fatigue- being constantly loaded as in a magazine is only half a cycle so really doesn't degrade the spring EXCEPT if the load is above the design limit. Sitting under a load ( within design) wont hurt it because it allows for that range)

Set (or 3 coil clashing)- this comes from rapid fire or excessive cyclic loading of a spring. Very common on car suspensions and rock crawlers, rock crushers in mines, vibrating conveyors in lumber mills and so on but not common in a weapon magazine

Beyond that, most spring failures result from other factors such as plating peeling, tooling marks, corrosion (mass loss)

Without actually measuring an unstressed spring then loading it-you really cant tell anything. This is why a lot of springs get replaced needlessly.

Try a good cleaning and proper lubrication first. ( and check the spring for wear/damage)
 
Originally Posted by marine65
I was looking at a web page to buy a couple extra mags and saw this

Grab a few spare magazines for your Bodyguard today, and don't forget to rotate your carry/loaded magazines every 3-6 months to ensure maximum reliability.

Please explain why?

Probably good advise to clean the whole works, magazine included, every six months or so. If I carried a gun I would.
Having said that an unloaded magazine still has the spring under tension.
 
Originally Posted by ABN_CBT_ENGR
That's probably not a concern but your skepticism is well warranted. I do enough NDT on springs in mining and conveyors and the failure modes are basically the same and here's how it goes. Starting with a properly engineered and built spring ( proper alloy, wire size, dimension and geometry with heat treat and plating if desired)……

The spring will eventually fade and fail due to cyclic fatigue- being constantly loaded as in a magazine is only half a cycle so really doesn't degrade the spring EXCEPT if the load is above the design limit. Sitting under a load ( within design) wont hurt it because it allows for that range) Set (or 3 coil clashing)- this comes from rapid fire or excessive cyclic loading of a spring. Very common on car suspensions and rock crawlers, rock crushers in mines, vibrating conveyors in lumber mills and so on but not common in a weapon magazine Beyond that, most spring failures result from other factors such as plating peeling, tooling marks, corrosion (mass loss) Without actually measuring an unstressed spring then loading it-you really cant tell anything. This is why a lot of springs get replaced needlessly. Try a good cleaning and proper lubrication first. ( and check the spring for wear/damage)

The magazines were new when placed into storage in a sealed bag so no dirt or foreign material were in them. I agree on your thoughts in principle, but I have seen it happen to other magazines as well so I cannot totally buy into the "springs weaken through use versus compression" concept. I believe that within reason (read this as <2-4 years) of storage there is no affect, but long term fully compressed springs do weaken. Just my experience with no science behind it.
 
Originally Posted by 2015_PSD

The magazines were new when placed into storage in a sealed bag so no dirt or foreign material were in them. I agree on your thoughts in principle, but I have seen it happen to other magazines as well so I cannot totally buy into the "springs weaken through use versus compression" concept. I believe that within reason (read this as Just my experience with no science behind it.


Even science must give way to reality and I'm speaking mainly from my own weapons experience as a dealer in the past as well as shooter and soldier- more so than an engineer on this particular issue.

What I have found over the few hundred mags I have torn down is that "distortions" ( leading to binding) and followers either wearing rough edges or cocking or various contamination cause the bulk of mag issues.

I have seen springs corroded and damaged but when assigning a failure mode, I call that a maintenance (operator) failure rather than the component because the spring cant maintain itself.

I have even made a few springs developing my own magazine designs ( for when I reopen and manufacture) so believe me, I take this issue seriously.

I cant really say I see other than maybe a fraction of a percent legitimately bad springs in either the weapon or the magazine.

Others may vary
 
Originally Posted by 2015_PSD
Funny, I found a fully loaded SIG P226 mag that had been in storage for more than 10 years (likely closer to 15) in a sealed bag and the spring was markedly weaker than the others that I had. It could be a one-off, but I am skeptical.
 
Originally Posted by Fattylocks
Having said that an unloaded magazine still has the spring under tension.


Not as much as a fully loaded magazine.
 
I don't worry about mag springs taking a set.

Mag followers seizing because of dirt, OTOH, that's happened to me. The subject was a no name aluminum AR-15 magazine that used at every opportunity (including practicing reloads and dumping it in the dirt) and never cleaned it. After about 2 years the follower seized in the mag body.

After cleaning the mag it was back to working fine and I'm still using it.

BSW
 
Another video showing that fully loaded magazines can cause the spring to take a set and shorten. How much set, and how long it needs to be loaded to take a set is dependent on the spring material and design.

If magazine spring set it will cause the gun to malfunction or not, that is also dependent on the magazine and gun. But the bottom line is that fully loaded magazines laying around for a very long time will cause the spring to take a set and shorten.
 
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