Keeping bullets permantly in a magazine

[philip964]

I now have the bullets and the magazines I want for my guns. I normally rotate through the magazines when I shoot. I would now like to take one magazine and load it with my zombie ammunition and use it only for carry. So it would be hopefully never fired.

Will this hurt the magazine over time. Will the bullets or the magazine eventually become unreliable.

Is this a bad idea? Should the magazine be unloaded and cleaned and replaced with new ammunition, every year, two years, five years?

Sorry in advance if this question has been posted before.

[Mike1951]

The magazine itself fares better staying loaded than enduring the unloading/loading cycles.

What you have to pay attention to are the top rounds. Rounds that are repeatedly chambered may suffer bullet setback and increased pressures.

So your process should avoid rechambering the same round(s).

[03Lightningrocks]

I have a magazine for my Glock 17 that was loaded for at least ten years. It was a magazine I kept in the bed stand drawer for a few extra rounds when the 17 in the weapon are just not going to cut it...lol.

[AEA]

WWII 1911's have been found in attics in duffel bags with loaded magazines that were fired and functioned flawlessly.

[Crossfire]

I think it is a good idea to change out self defense ammo once a year.

So, I shoot my ammo in my carry gun once a year, usually on my birthday, so I remember.

[MoJo]

I do the same as crossfire.

[03Lightningrocks]

With my carry weapon I do something similar as the others have mentioned. I fire off my self defense rounds first when I go to the range. It gives me a warm fuzzy to verify that in a self defense situation, all rounds from my weapon and the spare magazine will fire without a glitch. I found a bad follower in my PM9 because of doing this. It was one of those problems that only surfaced if firing hollow points. My practice rounds fed fine. Kahr sent me a new follower and i was back in business. I would hate to find a problem like that when it counted most. Had I not been in the habit of "emptying my carry rounds" down the barrel, I might not have caught the issue until it was too late.

[AEA]

with all of the above. I too fire my SD rounds yearly. But the main subject of the thread was Magazine springs.

That's why I mentioned the found WWII 1911's with rounds in the mag that functioned and fired flawlessly.

[03Lightningrocks]

with all of the above. I too fire my SD rounds yearly. But the main subject of the thread was Magazine springs.

That's why I mentioned the found WWII 1911's with rounds in the mag that functioned and fired flawlessly.

Keeping with the spring topic. I have read and heard it both ways. Some say it is no problems, others I have heard say it weakens the springs. I am not an engineer but it seems to me a spring that is kept compressed long enough could lose some ot it's memory on its uncompressed position. Enough to cause a problem? I am thinking no. I have yet to see it as a problem after many years of leaving loaded magazines in the safe or on a shelf.

[philip964]

Shoot and replace on my birthday, I like that, thanks.

[Jumping Frog]

Alright, I'll weigh in on this as I am a mechanical engineer, and I've also had this very discussion with a friend of mine who is a metallurgist.

In general, a spring that is compressed within its fatigue limits does not experience wear. Instead, it is the cyclical act of compressing/expanding a spring that creates fatigue. Fatigue is caused by cycles, which in the case of mag springs means loading and unloading. Leaving a PROPERLY DESIGNED AND WELL MADE spring compressed WITHIN ITS DESIGN PARAMETERS will not hurt it at all. Not even over YEARS.

Once again, only load/unload cycles count on the fatigue scale.

Expect a quality mag spring to soak up AT LEAST a thousand cycles. If you have enough ammo to be worrying about that many cycles, buy a spare mag or two..

You also need to make sure you do not overstress a spring. NEVER try to shove "extra rounds" into a mag. If it says it is a 15 rounder then only put in 15, not 16 (even if you are physically able to do so). Fatigue is a 3-stage failure mechanism and if you overstress a part enough you get to skip the first phase (pre-crack initiation) completely.

There are really three stress points of interest when discussing steel: Ultimate Tensile Strength, Yield Tensile Strength ("elastic limit"), and fatigue limit.

Here is an example: 4140 Cr-Mo low-alloy steel is very versatile. When quenched and tempered to about 180,000 psi Ultimate Tensile Strength (UTS) or roughly HRC 40 it has a YTS of about 120,000 psi and a fatigue limit of about 80,000 psi. So what do these numbers mean?

• If you load the 4140 to more than 180,000 psi in tension it will break.
• If you load it to between 120,000 and 180,000 psi in tension and then unload it you will have some deformation (yielding) that will not recover. Higher load means more deformation. The steel will not take many loadings like this. Think of bending a paper clip when you think of something stressed beyond its elastic limit.
• If you load it to less than 120,000 but more than 80,000 psi in tension and then unload it, it will perfectly recover its pre-load dimensions until after a certain number of cycles, whereupon it will break due to fatigue.
• If you load it to less than 80,000 psi and then unload it you could do this for 900 trillion (or more) cycles and it won't hurt the steel one bit.

So, if you have a high-cycle design part, like those found in internal combustion engines, you NEED to design in a stress range BELOW the fatigue limit. If you expect your part to last for 100 million or fewer cycles then you can design somewhere in between the fatigue limit and the YTS. But even a low-cycle design for fatigue will consider 10,000 cycles. One way parts, like those on missiles, can be designed in a completely different manner since they only make one go of it.

That said - I have had cheap mags break springs in just a few cycles. For self-defense I would carry only factory mags if I were you. Let the cheapies be for relaxed range time where a malfunction can't kill you.

Also the statement about only cycling hurting springs must be qualified with the following conditions:
1 - That they are good quality springs made by a reputable manufacturer
2 - That they are used within their design parameters
3 - That they are not subject to any unusually aggressive environment while stressed

[emcee rib]

Use epoxy if you want them in the magazine permanently. It's much safer than welding.

[WildBill]

Alright, I'll weigh in on this as I am a mechanical engineer, and I've also had this very discussion with a friend of mine who is a metallurgist.

In general, a spring that is compressed within its fatigue limits does not experience wear. Instead, it is the cyclical act of compressing/expanding a spring that creates fatigue. Fatigue is caused by cycles, which in the case of mag springs means loading and unloading. Leaving a PROPERLY DESIGNED AND WELL MADE spring compressed WITHIN ITS DESIGN PARAMETERS will not hurt it at all. Not even over YEARS...

Also the statement about only cycling hurting springs must be qualified with the following conditions:
1 - That they are good quality springs made by a reputable manufacturer
2 - That they are used within their design parameters
3 - That they are not subject to any unusually aggressive environment while stressed ...

Thank you Jumping Frog. That's about as good and clear explanation as I have ever read. Not overly technical, but it has all of the relavent information. Your post should be the final word on this subject, but when this question comes up again [and it will] we can just refer them to this link.

[C-dub]

Your post should be the final word on this subject, but when this question comes up again [and it will] we can just refer them to this link.

It should be, but we all know it probably won't.