Are we SURE compression doesn't weaken mag springs?

[kjaniak]

Worked in a spring shop and also an engineer.......

Another factor is the heat treat process they go through after manufacture. Variables in this step will give you differnet caracteristics batch to batch. Match this with raw material variables and you have two springs that meet print but have differnet half lives.

 

[IZinterrogator]

Every time I see this argument, 1911 owners come in with statements about leaving theirs loaded for years with no problems. I am beginning to think that single vs. double-column might have something to do with it. I bought the Wolff +5% mags for my M9 in Iraq, and they were taking a set over four months. Sure, the length doesn't matter, but the rounds were not being pushed into feeding position fast enough. My hypothesis is that the extra room in the mag allows other things to occur, like the spring twisting, which is causing these problems. Just my $0.02, any other similar experiences?

 

[RedST]

From an engineering standpoint, quality magazine springs should not lose enough strength from remaining in compression to cause a FTF. Repeated cycling causes coil wound springs to weaken. The spring will tend to creep, (change length) with temperature changes. This is really insignificant and not a factor affecting magazine operation.
From a shooters standpoint, I've seen way to many mishandled, dirty, and bent magazines. Magazines thrown on the shooting bench, dropped to the ground, stuffed into a hip pocket and sat on. Magazines that looked like they haven't ever been cleaned and lubed. I've seen some remove springs for cleaning using a twisting motion. One person forced a couple of large cleaning patches into an magazine to clean it and bulged out the side of the magazine. I knew of one shooter who took apart all his p239 9mm magazines, a total of six, for cleaning. When he reassembeled the magazines, followers and springs got installed in magazines they were not worn into. The result was FTF with four of the magazines. But it never fails, the magazine spring gets the blame for a FTF.

 

[Sam]

Look at magazines and how they are designed.
Put 13 rds into an original BHP mag (Circa WWII) and 13 rds into a modern 9 rated at 13 rds.
Notice the amount of effort required, notice that although the Browning is rated at 13 rds almost all will take 14 if you work a little harder and when the follower stops, it had bottomed against the floorplate, You will work a lot harder loading the rated 13 in the modern mag. Less tolerance. Designed to have everything rammed into the smallest place irrespective of outcome. On the modern weapon the spring will be bottomed out against the follower and floorplate. No play left in the spring atall. Same diff. between 7 and 8 rd 1911 mags.
There is less failure margin built into the system on the modern weapons. Everything is stressed a lot closer to failure, not just mags but frames, slides, internals take your pick. It is like the difference in construction between automobiles and airplanes. Car might be designed with a 6 or 7-1 margin between the design load and failure. Plane might be 2 or 3-1 between design load and failure. Still plenty strong to do the job but you are a lot more careful with it.

Sam

 

[Sunray]

Engineers dig holes.
"...about three weeks..." Isn't long enough. 300 years maybe. M-1 clips are springs. Ammo has been loaded in them for 50 to 60 years and they still work just fine.
"...the Browning is rated at 13 rds..." Commercial HP mags, yes. Inglis mags have always taken 14.

 

[JohnKSa]

CLEAR evidence that compression can weaken a spring.

http://www.funsupply.com/airguns/cocktest.html

Note that ALL of the springs weakened. Note that the weakening was EASILY measured. Note that the weakening progressed the longer the springs were left compressed.

These are very high quality springs made of excellent materials which have been specially treated to minimize wear and breakage while maximizing spring life. These springs are basically the heart of airguns worth several hundred dollars--they are just about as good as they can be.

It is worth noting that the springs in these airguns are typically coil-bound when the airgun is cocked.

I have a book on spring piston airguns that contains a similar test with similar results, I'll type in the results of that test and give a reference for the book if folks need more convincing. The author of the book now writes articles for the Shotgun News and is considered one of the foremost experts on airguns in America.

What's almost funny is that spring-piston airgunsmiths and makers have to know about springs to make a living. They'll all tell you to minimize the time the gun is left cocked to prevent the spring from weakening. I guess it's time that someone told them that everything they know about springs from lifetimes of experience is false.

The spring experts on the board can try to figure out how to rectify these real world results with what they "know" to be true. I don't know all the theory, but I know this, and what's more I can prove it.

Leaving springs fully compressed weakens them.

It can be demonstrated--what's more many of us have experienced this in real-life. Perhaps it's time to STOP pretending that it doesn't happen and instead try to explain why it DOES happen in some cases and why it DOESN'T happen in other cases.

 

[TheStook]

It comes down to heat treatment and purity. If the springs metal has dislocations or impurites than plastic deformation will be easier to occur be it through cyclical loading or compression.

 

[MR.G]

I have had problems with magazines that were left loaded and had the factory springs in them. Never had a problem with one that I have put Wolf extra tension springs in.

 

[Walt Sherrill]

JohnSKa wrote:

The spring experts on the board can try to figure out how to rectify these real world results with what they "know" to be true. I don't know all the theory, but I know this, and what's more I can prove it.

Leaving springs fully compressed weakens them.

The key part of that phrase is "fully compressed."

Lots of mags, fully loaded, don't leave the springs fully compressed.

My 10-round CZ mags use the same springs as my 15/16 round CZ mags. But when fully loaded, the 10 round mag hasn't compressed the spring nearly as far as the 15/16 round mags.

It would appear at the air guns in question are kept compressed at their design limits. Based on what Woff says on their website, that would lead to spring deterioration.

The comments from Wolff Springs, who seem to have comparable expertise with springs to the folks who build air guns, suggest that compressing to ther maximum design limits (exactly what seems to be happening with the air guns) will weaken springs, but compression at less than maximum limits is not a problem.

There is nothing inconsistent with what you assert and what Wolff asserts. Being MOSTLY compressed (but not fully compressed) isn't too hard on springs.

Neither the air gun experts nor Wolff seem to be all that concerned by cycling the springs, but the engineers with spring-related work experience who have participated here say that cycling can be an issue, too. One guy who spoke of cycling car-related springs millions of times said that cycling was not an issue. Guess it depends on the spring design/application?

 

[enfield]

No point in engineers arguing against those armed with anecdotal evidence and opinions. I surrender -- have at it.

 

[1911Tuner]

Arguing

enfield....

A Spring left fully compressed over an extended time will take a set and weaken. No way around that. It's under a constant strain. The point is that a good spring, properly made and within spec won't weaken to the point of failure for a LONG time, because the stress of being left compressed has been compensated for by the engineers who designed it *for a specific application*. In other words...they're fully aware of the rate that the spring will degrade under normal use, and that rate is figured in so that the spring will continue to perform its intended task for an acceptable amount of time.
They're aware too, that some people will leave magazines fully loaded at times, varying from one day to one year...or more.

Airgun piston springs are designed to operate over a certain range, and the guns come with instructions to release the load on the spring when not in use. Good idea to take the advice of the people who designed and built the machine. There are specific reasons for that instruction, likely to prolong the performance of the gun. Magazine springs...mainsprings...recoil springs, and the like don't come with such caveats. Yes, letting the spring completely release and stand free...any spring...when not in use will prolong its life.
Yes...Cycling those types of springs will cause them to fatigue at a faster rate than not cycling them. Yes...If a spring is compressed to the point of coil bind, it will fail earlier than one not compressed to the point of coil bind.
The reason is simple...The further it's compressed, the harder it strains to return to its uncompressed state. The harder you push on a wall, the faster your arms will tire.

It's all in the design and intended task of the spring for a particular application. Some designers overengineer a part, while others...don't.

Cheers!

 

[JohnKSa]

There is nothing inconsistent with what you assert and what Wolff asserts. Being MOSTLY compressed (but not fully compressed) isn't too hard on springs.

I agree completely with what Wolff says, and I have tried to make the point in the past that both full compression and spring quality are probably important issues that may not be addressed by the theory. However, the "experts" won't budge and continue to maintain that compression won't hurt springs--only cycling wears them out.

enfield,

That's a major cop out. The tests with spring-piston airguns go FAR beyond anecdotal evidence and opinions in that they can be easily reproduced for those who doubt the results. We're not talking about "cousin Frank who had a magazine once where the spring that got weak from staying loaded", we're talking about well described, easily reproducible tests showing quantitative measurements revealing that the tested springs are weakening from being left fully compressed.

I'm an engineer myself, and I must admit that my education has blinded me from time to time, but I finally figured something out. Education and theory are important to understanding WHY and HOW things work, but sometimes they can overlook important practical considerations. When theory appears to clash with reality, a person can choose to ignore reality, or a person can investigate the issue to determine why the apparent anomaly exists. Usually there's a good explanation, and often the information gained in the investigation is very useful.

So don't "surrender"! Figure it out and then tell us WHY it happens. Don't be one of the people who stops learning when he graduates.

 

[Gun Geezer]

me too

I am a mech engineer, also. It has been awhile since I had a metalurgy class, but I have had a lot of experience with spring steel in my work.

Even the best quality spring steel made correctly, tempered properly, and of correct composition can and will loose it's "springiness" if left under compression and especially if heated (not likely for a magazine spring) at the same time. Creep gets every thing over time. Just ask you grandma. Lesser quality spring steel can fail rather quickly under even mild compression or tension.

Anyone who has ever had a slinkly as a kid knows that if you pull a spring too far or compress it too much you can damage the spring beyond it's ability to return to it's correct length. However, that is not likely to be much of a problem with a magazine spring either.

More than likely you got a poorly made spring. It has happened to me before, but it is rather rare with good name brand magazines and springs.

 

[walking arsenal]

Perhaps we could divide this spring theory into two catagories such as double stack mags and single stack mags.

were doubles are worn more easier than singles.

Airguns hardly work in this theory as they are used in a different application entirely.

If we are talking just springs in general it works.

 

[JohnKSa]

Airguns hardly work in this theory as they are used in a different application entirely.

True, the only reason I brought them up was as reproducible evidence that compression could weaken high quality springs.

 

[enfield]

I didn't say compression set doesn't happen -- I said it doesn't HAVE to happen, not to the point that it degrades performance over a relatively short period of time. We have lots of evidence of spring systems that don't fail in compression set when used the way they're supposed to be used.

I don't doubt that air gun springs may fail due to compression set, but your assertion that they're high quality springs is an opinion. You don't know anything qualitative about the springs or their environment. Neither do I.

Regardless, air gun springs have as much to do with magazine springs as do the springs in your sofa.

Your air gun experience is not evidence that all magazine springs are doomed to fail due to compression set.

That's all I'm trying to say. Magazine springs don't have to fail. High quality parts can be produced, and are produced. If your magazine springs fail, try a different brand. If they continue to fail, try a different gun.

 

[Onmilo]

Once a spring reaches maximum compression it will not compress any further nor will it grow any weaker, period.
An airgun compression chamber spring is a lame comparison to a magazine spring.
Both operate under different principals and operate to create force for different reasons.
An airgun spring could be made strong enough to not take enough set that would adversely affect function even if left in a compressed state for an indeterminate amount of time.
The drawback would be in the fact that the airgun spring would be so strong as to make it nearly impossible for the average user to be able to cock the gun.

Gunsprings, actually all springs, weaken with repeated compression and decompression of the spring.
Springs do not weaken just because they are placed under a compression load, case in point are the coil springs under your vehicle. coil springs sit under compression from the time they are placed on the vehicle yet they do not wear out because of this compression.
Automotive coil springs wear out because of repeated cycles of compression and decompression that weaken the spring, not because of the engineered compression that they are under from the time the vehicle rolls off the production floor.

FAULTY springs can fail at any time during the life of the spring.
If your magazine failed because of a bad feed cycle that is an indication that the magazine spring was faulty or poorly engineered for the intended purpose in the first place.

 

[enfield]

Here's what may seem to be a radical idea:

If you're concerned that the magazine springs may fail in the mags you own for your carry pistol(s), then instead of storing the magazines empty, store them fully loaded!

If a magazine is going to fail, you want it to fail at the range, not in a defensive situation, so keep your carry gun magazines full and shoot often. Keep the good mags and scrap the bad ones.

Storing your carry gun mags empty may increase the chance that one will fail when your life's on the line. Springs don't fail on the shelf -- they fail under stress.

 

[fletcher]

The springs will not fatigue. However, they may undergo what is called "stress relaxation". Depending on the quality of the steel used in the spring, and the temperature at which it is stored, it may take anywhere from a few weeks (like if your mag came in a happy meal) to a year or more (most likely) to result in a noticeable difference.

 

[Walt Sherrill]

If a magazine is going to fail, you want it to fail at the range, not in a defensive situation, so keep your carry gun magazines full and shoot often. Keep the good mags and scrap the bad ones.

Storing your carry gun mags empty may increase the chance that one will fail when your life's on the line. Springs don't fail on the shelf -- they fail under stress.

Mag springs generally don't fail catastrophically. They tend to get weaker and finally fail to function properly. That can still happen, regardless of how they are stored. Storing them empty might delay the failure -- but it won't stop it, nor make it any more predictable.

 

[JohnKSa]

Your air gun experience is not evidence that all magazine springs are doomed to fail due to compression set.

True--but I never claimed anything even slightly resembling this remark.

I didn't even say that AIRGUN springs were doomed to failure from compression set. They typically fail for other reasons--they DO, however WEAKEN from being left fully compressed.

You don't know anything qualitative about the springs ... Neither do I.

Well, HALF of that assertion is correct. But it's only correct because the person who doesn't know anything qualitative about the springs isn't interested in doing some relatively simple research.

Springs do not weaken just because they are placed under a compression load

I didn't say they did. I said that springs weaken when left FULLY compressed.

Both operate under different principals and operate to create force for different reasons.

True, but you'll note that in the test, the springs were only left compressed. Just like the springs in a fully loaded magazine might be. So, while they NORMALLY operate differently, in this particular test, the testing mode was remarkably similar to the kind of stress fully loaded magazine springs might be under.

An airgun spring could be made strong enough to not take enough set that would adversely affect function even if left in a compressed state for an indeterminate amount of time.
The drawback would be in the fact that the airgun spring would be so strong as to make it nearly impossible for the average user to be able to cock the gun.

Likewise magazine springs, but you'd never be able to load the mags.

If your magazine failed because of a bad feed cycle that is an indication that the magazine spring was faulty or poorly engineered for the intended purpose in the first place.

So, all the airguns had faulty or poorly engineered springs? Seems a stretch...

Ok, here's a question.

Are you guys REALLY saying that the compression depth of a spring has absolutely no bearing on its longevity/durability? In other words, if you compress two completely identical high-quality springs to differing amounts (say, one to half of full length and the other to fully coil-bound) and leave them compressed for 10 years, that there will be absolutely no measurable difference in the length or strength of the two springs when they're decompressed after 10 years?