Swapping out your carry mags?

[Draken]

Cycle out carry ammo, especially on a gun carried daily. Friction from the powder moving will turn it into unignitable fine powder.

Thats been proven to be a wives tale. Guy with a high power microscope did a multi-year test with ammo in a tumbler, and if you didn't know what was control, and what had been tumbled for over a year, you wouldn't have been able to tell the difference.

Moisture is more likely to cause your powder to not ignite properly than any "breakdown" of powder.

[GreaseMonkeySRT]

Thats been proven to be a wives tale. Guy with a high power microscope did a multi-year test with ammo in a tumbler, and if you didn't know what was control, and what had been tumbled for over a year, you wouldn't have been able to tell the difference.

Moisture is more likely to cause your powder to not ignite properly than any "breakdown" of powder.

I wouldn't doubt that. I've had 1-2 year old carry ammo where one round wouldn't ignite, even after two solid primer strikes. Moisture makes more sense.

[10x25mm]

The magazine spring property which is critical to the functioning of automatic firearms is force. Spring force is the (multiplication) product of deflection times spring rate:

Spring Force = Deflection x Spring Rate

Deflection changes as a helical magazine spring is compressed or unloaded by cartridge count changes. Helical spring rate only changes (for ferrous springs) when cracks or severe corrosion develop in spring wires, reducing their effective cross sections. The spring wire in helical springs is loaded in torsion, a loading mode which usually promotes cracking before any noticeable plastic deformation occurs. So you will not know that spring rate has changed unless you magnetic particle or dye penetrant test the spring wire. But it usually doesn't change in magazine service.

Helical spring deflection is directly affected by spring set, the tendency of some helical compression springs to reduce free length under prolonged loads due to metallurgical structural effects (mostly grain boundary and dislocation glide). The starting point for spring force generation keeps lowering, reducing full range spring force. As a spring sets, its force at any given deflection declines by the set (length loss) times the spring rate.

In the case of magazine springs, gun designers understand that spring force declines from the first round stripped from the magazine to the last. They design the magazine spring for any given weapon to provide reasonable force when the magazine is full and minimum acceptable force when the last round is stripped and the follower has to actuate the bolt hold open. It is a balancing act. Eventually, in service, a set magazine spring becomes unable to fully present the last few rounds' bases to the slide or bolt on its return stroke, or it cannot lift the bolt hold open (slide stop) with sufficient rapidity to hold open the bolt or slide.

The rate of magazine springs rarely change (cracks and corrosion are unusual), but spring force deteriorates as spring set occurs. So the key to maintaining magazine performance is to monitor unloaded (free) spring length. When you take your magazines apart for cleaning and oiling, measure the free length (unloaded length) of your magazine springs. Have they shrunk? The amount of shrinkage acceptable varies from weapon to weapon. Fast cycling guns don't tolerate much spring set. Slow cycling firearms (e.g. bolt action rifles) are not affected until the set is severe.

[Roundballer]

Yep, tumbling power is one of those myths that won't die. If you can't accept empirical evidence, how about an NRA article about it:

https://www.americanhunter.org/conte...mmo-dangerous/

And, a well made mag spring will not have any issues loaded for long periods of time. Just "google" the article "American Handgunner , May-June, 2003 by John S. Layman"

[slingshot77]

Cycle out carry ammo, especially on a gun carried daily. Friction from the powder moving will turn it into unignitable fine powder.

You need to call Hornady on this as they have done some long term testing on this. Per my call to Hornady, and based on their testing, the the powder moving around inside the case doesn't reduce or break up the powder like some think. What they did say is with certain powders that have a flame retardant coating on the powder to slow the burn rate that coating could be effected (they didn't elaborate) and that can slightly change the pressure curve as the powder ignites and burns. My call was specific to high pressure rifle rounds so how this effects lower pressure pistol rounds I don't know.

But I did have some old .357 magnum (loaded with old metal can 2400) many years ago. I had this stored in the attic of my barn (I didn't even know that I had it until I found it when looking for something else). It was really tarnished from long term storage. I pulled a couple of bullets to sniff the powder to see if it went sour. It smelled good so I ran those rounds in my tumbler (probably 20 or so hours). Those rounds all shot, & sounded good with no signs of over-pressure and not one mis-fire in the 198 rounds.

[MCPO_SOCM_RET]

Thats been proven to be a wives tale. Guy with a high power microscope did a multi-year test with ammo in a tumbler, and if you didn't know what was control, and what had been tumbled for over a year, you wouldn't have been able to tell the difference.

Moisture is more likely to cause your powder to not ignite properly than any "breakdown" of powder.

I do not doubt that at all. But like others here have experienced, I've had a few rounds fail to fire after carrying the loaded mag and extra mags.
If I don't have them bouncing around every day for a year or more, I generally don't even give them a second thought - they're usually in the moisture controlled safe, or my temp/humidity controlled vault. I call it a vault because the full size door is S&G tumbler safe door.
Bring a jackhammer if I forget the combo., we have a lot of 18" poured re-barred 8000psi concrete to bust through. Yeah, overkill - and off topic now. Mea culpa.

[Roundballer]

I wouldn't doubt that. I've had 1-2 year old carry ammo where one round wouldn't ignite, even after two solid primer strikes. Moisture makes more sense.

WD-40 will do that too, kills primers.

[dirtmcgirt76239]

>> Typically a loaded mag (even for years or more) can't lose spring RATE as a lot of shooters suggest as the spring rate is figured from wire diameter and number of coils

If you've ever seen an old car sagging on its coil springs, you know that's not true.

Think of a diving board: If it were made of steel and strong enough, it would never bend too far, and never lose its elasticity. But if you bend it with excessive force, there is a thing called the "elastic limit", beyond which the board will not return all the way.

The details of this depend on metallurgy, heat treatment, and in magazines, on the exact geometry. Loading the magazines with one or two fewer cartridges than full capacity is probably a good way to make sure springs will not fatigue. I don't actually know that spring fatigue is still a problem in modern magazines. Material science marches on.

But it's not a silly thing to be concerned about.

I think the word they use is cycles. You can load a quality commerical or military mag, put it in a drawer for 40 years in a dry house and I would be my life on it.

For the purposes of the OP, if he hasn't vetted all his mags, vetted the gun, have a ton of experience, you might just shoot it off every 6 months just to do it, takes some notes, mark the mags etc.

If you have the same mag for 20 years, throw some new springs in it if you are worried, and it saw a lot of use.

Its not over bending though, thats not a thing, this is designed to compress to what the mag will hold. Its doing it thousands of times that changes the wire. Putting in 13 rds in a 14 rd mag wont make a difference. You can put in 14.