Rifle magazine spring wear

[Fly320s]

We've discussed this before, and I think most people here already know this, but just in case you don't here it is again from Duane Liptak of Magpul.

I’m seeing a greater understanding lately in online discussions that springs don’t wear out from remaining compressed, and that’s refreshing. A PROPER spring only wears out through repeated cycles. You would shoot out dozens of rifle barrels using a single PMAG before the AR-15 magazine spring became a limiting factor or a wear item from cycling. You can leave them, and any good mag, loaded indefinitely with no ill effects. So, don’t worry about swapping mag springs.

https://www.arbuildjunkie.com/ar-15-magazine-basics-performance-overview-duane-liptak-magpul/

The whole article is an interesting, in depth discussion on AR15 magazines.

[MechAg94]

Thanks for sharing.

[AJ Dual]

Anecdotal testing from people who've left mags loaded for years shows that the springs do indeed take a set as compared to factory-new, but OTOH, the spring is still more than long enough (several times the magazine length when removed and uncompressed) and functions properly.

So I'm in the camp that it does affect the spring, but is still a non-issue.

[dogmush]

My understanding of spring engineering (which is not professional grade, but not none, and I have successfully made working springs) is that a new spring takes that "set" very early on in it's operational life.  For mag springs that's like 10-15 cycles.  Then it just holds that [new] uncompressed length basically forever, or until it gets enough use cycles that it looses it's elasticity and is "worn out".

It is possible you can get that "initial set" from loading once and leaving compressed as well as the "break in" cycling that normally happens.  Properly engineered springs take this into account, for example if you replace the coil springs on your car you are supposed to let them "settle" for a couple days or a short drive before setting final ride height, as it will change a little.

[MechAg94]

I remember reading or hearing years ago that some metal body pistol magazines can develop dimples where the rounds press on them potentially causing them to hang up.  I always heard that was why BAR gunners back in the day were trained to knock their magazines on something before putting them in the rifle.  

I had bad experiences with ParaOrdnance mags back in the late 90's.  Later one, Para made their own stamped magazines which worked a lot better.  It seems most manufacturers do a better job with magazine design or at least they know who to go to build them.

When I first got an AR in the early 2000's, I had bad experiences with the cheap gun show magazines I bought.  Once I figured out who sold better quality magazines, everything worked a great deal better.  

[Perd Hapley]

MechAg, we were taught to slap our AR (M16) magazines against our helmets before loading the gun, to ensure the rounds were seated to the rear. I still slap magazines against the heel of my hand sometimes.