[Tinkerhell]

Something I've been meaning to research and just haven't made time so I thought I'd ask and see what others here may know.

Mag springs. I know of an armorer or two that say you absolutely should not keep a mag loaded to max for a long period - like keeping 5 - 10 loaded mags in your safe. Just in case you know... They say that because the spring will weaken & end up causing failure to feeds on the bottom end of the stack.

Conversely I've heard mechanical engineers tout that that's not how a spring works. That, if it's a quality mag, then the spring should be made from and designed to hold up to the pressure of a full stack indefinitely.

Finally what about springs wearing out? If I end up running 1000 loads (not rounds, full mag loads) through a mag will the spring weaken/deteriorate? Assuming that I keep em cleaned, don't store them in a bucket of swamp water or use them to drive nails etc etc.



Opinions? Research? Anecdotal evidence?

 

[slabertooch]

well i guess you could point to the springs/coilovers on a vehicle. From the time they are put on they are compress, and usually last for quite some time. It's the compress/release cycle that will weaken a spring, much like bending a piece of metal back and forth to break it.

that being said, when I was in the Marines we were always told to keep them loaded, the main reason most magazines failed was because (1) they are cheap to begin with, and (2) aren't really designed to hold 30 rounds. We would load with 28 rounds. If you could easily hand load 30 rounds into a magazine, good chance that you would have a Failure to Feed/Load. if you had to force 30 rounds in, you were almost guaranteed to have double feeds the first couple of rounds.

Good quality magazines should be able to hold full capacity for an extended time. If you shoot on a regular basis, I would have additional magazines on hand, and would recommend changing then out every once and a while.

From personal experience, I carried a M9 pistol as part of a security team for my unit. We had the same rounds (except after we fired), same pistols, and same magazines, for over two years. Not once did we ever experience a failure to feed, or eject.

 

[Firearmz]

Quality magazines can stay loaded.

 

[Ashe]

I keep about 10 fully loaded mags for my AR and 5 fully loaded mags for my pistols at all times. If the springs are quality they will keep for a long time.

My father was going through my grandfathers attic a few years after he died and he found a 1911 in a shoebox in the bottom of a trunk. He had to clear it because it was cocked and locked with a full mag. My grandmother said that my grandfather had put that trunk in the attic about 5 years before he died.
Best Case scenario the mags were only sitting loaded for about 3-4 years, with the odds of the mags sitting there loaded for arounf 9 years pretty good.

After going to the range with the pistol I can report that the pistol worked fine, the ammo that was in the pistol worked fine, and the magazine functioned flawlessly.

 

[Jmark]

Yup, as other posters have said it is the cycling of the springs that wear them out, not keeping them compressed. Keep in mind though all mags aren't made the same and there are many composite mags that will have feed lip failures if left loaded for too long.

 

[Rammstein]

I've covered this here twice.

Ok...the science behind it.

Springs made of good metal are designed to withstand the tension from a specific range of motion. Firearms engineers know and understand this concept and have designed their magazines to be able to reliably function through this range of motion.

Point X is minimal compression; that is, the point where the only tension on the spring is the resistance from the follower pushing on the feed lips of the magazine. Point Y [fatigue limit] is near maximum compression; that is, the point where the magazine is loaded to full capacity. Point Y+1 is when the spring is stressed passed its structural limitations. When this happens the atoms in the metals shift and the lattice changes. When the lattice changes, any imperfections in the metal becomes more pronounced.

Magazinesprings using quality metal will have less imperfections, thus they will be harder to deform.

Pushing a spring beyond its yield point causes the spring to deform. The spring in your magazine was designed to hold X number of rounds; therefore putting X number or rounds in your magazine and keeping them there does no harm to the spring. Now if you were to force X+1 rounds (and if it actually fit) then the spring would be forced beyond its structural limit and cause it to deform.

Now having said all the above it is important to note that exercising the spring within its normal dimensions is not going to create a significant amount of creep*, so don't be too worried about using the magazine too many times. But remember, having the magazine spring compressed within its structural limits does not do harm.

Any spring that is at a normal temperature (read: not in a furnace) unless there is too much stress placed on it.

Hooke's Law of Elasticity which applies to linear-elastic materials (like springs) basically says that a spring will deform when pushed past its elastic limit.

Since the spring in your magazine is most likely steal it will obey Hooke's Law.

So don't worry about loading (and keeping it loaded) your magazine to its intended capacity.