Can you Store Magazines Loaded? (Yes, Here's Why)

You've heard it before: If you store a fully loaded magazine long-term -- say, six months or longer -- then you might as well throw it away. That magazine's spring is ruined and unreliable, because it wore out.

You might've also read that you shouldn't store magazines fully loaded, but that you instead leave space for one or two rounds because this reduces the stress on the spring, preventing it from wearing out.

These are both myths. You can store a fully loaded magazine basically forever, and the spring will not wear out. But simply giving you the answer isn't enough -- we get it. So, here's why it's perfectly fine to store your magazines long-term, fully loaded, with no concerns about future spring wear.

Magazines Springs Wear From Repeat Use

When it comes to a magazine spring's life expectancy, there are three important things to consider: Elastic deformation, plastic deformation, and fatigue.

• Elastic deformation describes how much a spring can be compressed before it permanently deforms.
• Plastic deformation is the point at which a spring permanently deforms from being compressed too much.
• Fatigue is the wear that a spring suffers over time, caused by being repeatedly compressed and decompressed.

In normal use, a magazine spring will never experience plastic deformation from being left fully loaded, for any amount of time. Manufacturers purposefully design magazine springs to have a greater elastic deformation limit than they'll ever experience under normal use.

In other words, the springs in your magazines are made to handle more compression than what the magazine capacity allows for. This ensures they'll never experience plastic deformation simply from being loaded.

Fatigue, on the other hand, is inevitable. Each time you compress and decompress a spring -- in this case, every time you load and empty a magazine -- the spring develops microscopic cracks. These tiny cracks eventually cause the spring to lose the ability to rebound when compressed, or they can cause the spring to simply break.

Storage Doesn't Cause Spring Fatigue

Simply loading a magazine once and then storing it with the spring compressed is never going to cause fatigue. It takes tens of thousands of loading and unloading cycles to cause a magazine spring to experience enough fatigue to fail. In a lab stress test, it took nearly 70,000 cycles to wear out a Magpul PMAG's spring. In that same test, it took nearly 15,000 cycles to wear out a GLOCK magazine's spring.

"What About Stress Relaxation?"

Chances are, you've seen a pseudo-scientist on a gun forum bring up something called "stress relaxation." This phenomenom is the decrease in stress of an object in response to experiencing a constant strain over time. This can cause an object placed under stress to change shape.

In the case of a spring, stress relaxation can cause it to shorten from being stored compressed. Put simply, if you measure a spring's length at rest, then compress it for awhile, then decompress it and measure it again, it will be shorter.

Stress relaxation of a spring from prolonged storage under load is not a cause for concern.

Here's why: The force a spring exerts is directly proportional to how much it's compressed. This is known as Hooke's Law (f = kx) or, in simple language, "Spring force equals spring stiffness multiplied by compression." The more a spring is compressed, the more force it produces. The less a spring is compressed, the less force it produces.

Hooke's Law is why stress relaxation doesn't matter. Even if a magazine spring loses a small amount of length at rest (which takes years of storage under loaded) the amount of force the spring is still able to generate when compressed is so great that it will easily overcome the resistance of the ammo it needs to feed.

By the time a magazine is nearly empty, the amount of force the spring must exert to feed the final few rounds is so small that any loss in the spring's uncompressed length from loaded, long-term storage is negligible and inconsequential.

This has been repeatedly tested and proven to be a non-issue.

This guy proved it. He loaded some AR-15 magazines for 20 years, measuring spring lengths before and after storage. He found the springs only lost 1.5% of their length and had no issues cycling.

This guy proved it, too. He stored GLOCK magazines fully loaded for five years and found they lost minimal length, exhibited no failures to feed, and suffered no other concerns where reliability's concerned.

"But Don't Feed Lips Bend From Long-Term Storage?

No, magazine feed lips will not deform from long-term storage, even when fully loaded. That holds true even for polymer magazines, like Magpul PMAGs . This guy stored a fully loaded AR-15 PMAG for 12 years (with no cover) and had zero issues cycling the 30 rounds it contained.

This is because, like magazine springs, magazine bodies and feed lips are built with elastic and plastic deformation in mind. When used as designed and loaded to capacity, magazine feed lips will only ever experience slight elastic deformation; they will not experience plastic deformation (warping).

(You Should Still Cycle Your Magazines)

We all like to keep a couple "emergency" magazines loaded for that unlikely-but-not-impossible "SHTF" scenario. But you should still swap those loaded and stored magazines. Inspect them to ensure they're in good condition, cycle them, and replace them with other magazines to keep a rotation going.

The reason for this is simple: Environmental effects can still take a toll on your magazines. Moisture can penetrate a magazine and corrode its interior walls and the spring which will likely cause it to fail to function reliably.

If subjected to extreme temperature changes in storage, polymer magazines can also warp over time. Cycling your magazines every few months helps to ensure they remain in good working order.