PMCS your gear and don’t forget the magazine springs

[davidjinks]

First…..PMCS your gear. All the parts and pieces that go in to it.

Second…..these magazines were loaded 3 years ago and put in my chest harnesses for storage. They are new Glock 17 Gen 5 magazines, function checked for a full mag, cleaned, loaded, and stored.

Would they work? Probably. A couple of the mags the rounds just kinda fell out. That’s a significant set those springs took though.

Magazine #1 of 8. New OEM 10 coil Glock magazine spring on right, replaced 10 coil on left.

https://i.imgur.com/2oMpsrV.jpg

Magazine #7 of 8. New OEM 10 coil Glock magazine spring on right, replaced 10 coil on left.

https://i.imgur.com/yxWnoMg.jpg

Old spring left, new spring on ruler.

https://i.imgur.com/LF9AaHd.jpg

8 old magazine springs, and 2 new OEM mag springs in the middle.

https://i.imgur.com/pSk8LPY.jpg

[markm]

I wonder how long it takes to get to the shorter spring length. A week? A month? A year? etc

[davidjinks]

Hmmmmm……….

I’ll set something up.



I wonder how long it takes to get to the shorter spring length. A week? A month? A year? etc

[markm]

Hmmmmm……….

I’ll set something up.

It would be interesting to observe. I started rotating rifle mags that had been in guns loaded after someone here posted some spring degradation info. There was some amount of spring recovery noted after a year or so uncompressed if I remember right.

[davidjinks]

Rifle mag springs will be next for change out. I’ve got mags that have been loaded for 13 years in storage boxes.


It would be interesting to observe. I started rotating rifle mags that had been in guns loaded after someone here posted some spring degradation info. There was some amount of spring recovery noted after a year or so uncompressed if I remember right.

[SomeOtherGuy]

So... exactly the problem that we've been told for decades is NOT a problem. With a brand generally known for quality and consistency. Interesting.

How many threads are there here and elsewhere repeating that springs wear out from cycling, not from constant compression?

Any chance these are just a defective batch of springs? Would they have been made during the Covid-19 festivities?

[davidjinks]

These are pre-Covid direct from Glock.

The replacement springs are post-Covid OEM from Midwest Gun Works. I’ve got magazines pre, during, and post-Covid but I haven’t seen any differences that I can note.




So... exactly the problem that we've been told for decades is NOT a problem. With a brand generally known for quality and consistency. Interesting.

How many threads are there here and elsewhere repeating that springs wear out from cycling, not from constant compression?

Any chance these are just a defective batch of springs? Would they have been made during the Covid-19 festivities?

[markm]

So... exactly the problem that we've been told for decades is NOT a problem. With a brand generally known for quality and consistency. Interesting.

I'm not sure this is a problem. The observation was documented on USGI mags if I remember correctly. Nothing unique about Glock.

There's no need to hit the panic button. There's zero chance I'm tearing down my Glock "clips" to change springs unless there's functional problems to prompt that action.

[davidjinks]

I agree with markm. This is just something I found during PMCS and thought I’d share it.

Markm, I took measurements of the old springs (3 randomly chosen ones) and I’ll monitor the once a week to see if they start to return to semi normal set. I’ll also pull down 2 mags from my harnesses once month and doe some measurements.

This is of course my schedule permits I’m my old ass doesn’t forget.


I'm not sure this is a problem. The observation was documented on USGI mags if I remember correctly. Nothing unique about Glock.

There's no need to hit the panic button. There's zero chance I'm tearing down my Glock "clips" to change springs unless there's functional problems to prompt that action.

[Disciple]

I would be interested in seeing a new spring that has been fully loaded and unloaded at least three times next to one of the old ones.


So... exactly the problem that we've been told for decades is NOT a problem. With a brand generally known for quality and consistency. Interesting.

How many threads are there here and elsewhere repeating that springs wear out from cycling, not from constant compression?

I'll take the advice of someone who seems to know what he's talking about over mindless repetition of a talking point.


Actually, magazine spring life is not as simple as "load and leave - they will last forever", or "cycling is the only thing that wears out magazine springs".

In 1966 the Army did a five year study on this very subject. A report entitled "Evaluation of Pretreatment Process and Long Term Storage on Magazine Springs" was published with the results of this test.

There were two objectives, 1) determine the effect of various pretreatments on spring life and 2) determine the effects of long term storage of magazines stored at normal, hot, and cold temperatures. The parts we are concerned with are the life of a "normal" spring, as none of the pretreatments yielded cost effective improvements, if any improvement was seen at all, and the results of extended storage of fully loaded magazines versus unloaded magazines over 5 years of storage.

(Data from "Evaluation of Pretreatment Processes and Long Term Storage on Magazine Springs".)

LONG TERM STORAGE:

In order for the "spring to not take a permanent set in service" the spring must never be loaded beyond specifications, which is generally not more than 50% of the free length. Most magazine designs have the springs over-compressed when loaded to maximum capacity. M16 magazines are such springs, when fully loaded, they are compressed to 14% of their free length (18% if you only go to 28 rounds).

The magazines, some loaded and some unloaded, were stored for 5 years, at set intervals a portion of the springs were removed from storage and had the free length and load-at-length measured, the ones removed from storage did not return to storage after testing. After approximately, 12 weeks the loaded springs had free lengths reduced below the original value, and lost strength, around 84% specification value. After 24 weeks, the load-at-length values were 76% there original value.

From 24 week the loaded springs showed a very slight decrease in both length and strength, dropping to about 72% after 2 years and stabilizing at that value after that. After 1-1/2 years, in the loaded condition, spring exhibited an average set of 11% below the initial free length. This stabilized for the rest of the test period.

This indicates that the strain on the spring has an effect on the loss of strength and length, but if the strain is constant the reduction reaches a stabilization point, and how low that point is depend on the initial strain. Unloaded magazines also showed a decrease in free length and load-at-length values, but stabilized in 24 weeks just inside the acceptable drawing limits.

The functional testing of the magazine after storage was to fire all of the loaded rounds in them and see if there were any magazine attributable malfunctions, there were none.

So, you do loose a measurable portion of your spring strength after long term storage, but it will stabilize after approximately 2 years. A spring with a strength of 72% of its new specification strength does not adversely effect function, but it has some impact on total life, as we know cycling of the spring will also lead to loss of free length and strength.

SPRING LIFE:

Spring were gymnasticated at a rate of 116 strokes per minute between the assembled height (unloaded length) and the maximum design compression (fully loaded length), with the free length and load-at-length checked a set intervals. This cycle rate was considered a bit excessive, but as the in service cycle rates would be slower this was the "worse-case". By 1655 cycles, about 1/3 of the springs' load-at-length value had dropped below the new spring limit, and by 12,000 cycles, all of the springs had dropped below 50% load-at-length (which is probably insufficient for proper function), or had become so distorted cycling was impossible.

DISCUSSION:

The service limit is not necessarily the same as the production limit, and according to this study, a spring with 72% of the production limit is capable of providing adequate performance. However, it would be incorrect to say that long term storage of fully loaded magazines "has no effect on the spring". On average it took about 700 to 1000 cycles to reduce the spring strength values from "new" to 72%, so that much spring life has been lost. So, it depends on how often you load and unload your magazine, as to which is better for the life of the spring, storing loaded, or loading and unloading.

The up-shot is: It doesn't make any noticeable difference as to the question of "Which is better for a spring, loaded or unloaded?"

EDIT: If you want to know when your spring is near the end of its life, when unloaded, the force need to depress the second round in the magazine should not be less than 2.5 pounds, preferably closer to 3 pounds.

[ST911]

I'm still using some G19 mags from ~1994 (?) A-serials. Not recommended, but they keep working so they're still range mags.
I had 2 out of 3 G45 mags go bad within ~20k rounds, the third is still running.
~2012 G19 and G17 mags at 50k plus, still good range mags.
A few G19/G17 mags here and there came unzipped over 2-3 years in duty guns.
Mags are weird like that. Check em periodically. Don't get attached.

[FromMyColdDeadHand]

Stupid question: Can you 'stretch the spring back so that it rests at full normal length and call it good?
Are there different spring materials that work better? The braided, versus spring steel, versus ?
The absolute crush that we put springs through for a full mag does make sense that standard spring knowledge might not apply to the gun usage?

[jsbhike]

Stupid question: Can you 'stretch the spring back so that it rests at full normal length and call it good?


It might give a temporary boost, but not a long term kind of thing.

[davidjinks]

You could, but it stresses the material out more. However, I’m not a metallurgist so I’m only going on what I’ve learned over the years.



Stupid question: Can you 'stretch the spring back so that it rests at full normal length and call it good?
Are there different spring materials that work better? The braided, versus spring steel, versus ?
The absolute crush that we put springs through for a full mag does make sense that standard spring knowledge might not apply to the gun usage?

[davidjinks]

They would normally go right in to the training mag box, however these mags have only been function checked and loaded/stored. So a spring change is simple insurance.



I'm still using some G19 mags from ~1994 (?) A-serials. Not recommended, but they keep working so they're still range mags.
I had 2 out of 3 G45 mags go bad within ~20k rounds, the third is still running.
~2012 G19 and G17 mags at 50k plus, still good range mags.
A few G19/G17 mags here and there came unzipped over 2-3 years in duty guns.
Mags are weird like that. Check em periodically. Don't get attached.