Magazine question...

Just curious as to your opinions on leaving a magazine loaded in the context of spring fatigue. I've read both opinions...leave it loaded, it doesn't matter and unload it and load a second one to allow the magazine spring to relax. The last semi-auto that I owned was a S&W 4506 and I used to unload the magazine every couple of weeks and load the other. FYI, I have a Stoeger Cougar in 40mm which has a magazine spring I swear was taken from a '59 Pontiac and a Ruger P95 in 9mm. So...what say you?

Thanks!

David

Quote:

---

Originally Posted by David_Pavlich

Just curious as to your opinions on . . . So...what say you?

---

This topic arises often. Like a vampire, it is never truly laid to rest. Even though we try with "our wooden stakes".

If you search this forum, and the 'Net you will find a ton of info.

I claim "some passing knowledge" as a retired mechanical engineer with 31 years at a "major" automobile manufacturer.

First, we must assume that the magazine manufacturers have "done their homework" and selected the "proper steel" for the springs.
In the real world, it is always possible to screw things up. Sometimes technical ignorance, sometimes simply "cost".

Given proper steel, and proper manufacturing techniques, it would be VERY hard to reach the thousands (hundreds of thousands)
of cycles needed to achieve "spring fatigue" to failure. And, leaving the spring compressed will NOT affect its life cycle to fatigue.

Given that, it is possible to screw up design and material parameters through "ignorance" and have springs which quickly "take a set".
Shouldn't happen, but it can. See above for "technical ignorance" and "cost". And "human involvement".
For these same reasons, it is possible to "make" springs in which a significant number will "fail early". Often this is VERY early.

There is a whole area of "engineering" in which testing and quality control measures verify "proper life cycle design" for springs.

For an example of what properly designed springs do millions of times a day, think of automobile engines and their "valve springs".
I will leave it to "the student" to determine how many times a single valve spring cycles during a theoretical 100,000 mile vehicle life.
Hint: a typical engine spends a lot of time between 1,500 and 3,000 revolutions per minute (RPM). And a lot of "minutes" in 100,000 miles.
Hint: while the vehicle is just "sitting around" waiting for the owner to use it, some valve springs are compressed, and some are not.

Or, for an at home example, my Beretta 92 was purchased in 1992. Both magazines have been loaded all the time since then.
Well, except when being fired dry, and then reloaded. Never a failure to feed in thousands of rounds.
I guess Beretta has "learned some things" since they started firearm manufacture back in 1550 or so. :mrgreen:

As always, YMMV. :smt1099

Now, that's a really good, definitive answer to this recurring question.

Thanks, Dan! I thought the same thing, but never had someone with your background explain it. And considering that the spring in the Stoeger is REALLY stiff, I was able to get all of 5 rounds in without the "helper", I would think it would have a half life of about 250 years! Consider the stake driven.

David

I concur with Steve,that is probably the best answer I've ever heard for that question.I have to admit I thought initial set was basically normal though.

Dan I like your answer. Of course though I am still slightly paranoid. I buy extra mags and every 2 weeks I swap them out and basically give them a break. I'm just anal like that.

I read an article that was written by an Engineer at Wolff Springs. He said that it is the constant up and down motion that wears out a springs tension, and not being compressed. Brevard13, I'm like you and do about what you do with the magazines. Just my personal preference here.

I've been told that the more you move the spring , it causes more fatigue so if loaded , leave it loaded or vise versa.
If you don't like leaving a round in the chamber , eject mag then eject round .

A magazine spring, like any other piece of metal, wears / fails from use or movement.

Load your mags up and forget about um. :watching:

You mean to tell me I don't have to change the coil springs on my car monthly?tumbleweed

Quote:

---

Originally Posted by TOF

You mean to tell me I don't have to change the coil springs on my car monthly?tumbleweed

---

If it's a Dodge, then only every 3 months.