Recoil Spring Longevity

[Walt Sherrill]

Nah, I'm more interested in reliablility, if it ain't broke don't fix it.

Nothing I suggested is likely to negatively affect reliability. In fact, it might improve reliability. (And, if you aren't happy with the changes, you're just out a few bucks for springs -- and can put the old springs back in.)

Brass that is sent to hell and gone means that more recoil is going into the frame (and shooter's body) than is probably appropriate, and less force is being stored in the spring to cycle the slide. That could lead to wear on the gun, or make the shooting experience less pleasant. It will likely get worse, not better -- and if the spring gets weaker, over time, it may eventually not chamber rounds properly -- as it may not have enough stored force to work the slide properly.

If the spent shells from your 1911 are dropping nearby, you have a strong recoil spring, and you may experience some failures if you go to a lighter-shooting (less powerful) round. But that won't be a problem if you just try the new rounds before you have to rely on them to make sure they function in the gun properly.

As you say, if it's not broken you really shouldn't fix it, but addressing some of the symptom of a potential (or upcoming) break can keep you from having it break later, when it might matter.

.

[Bill DeShivs]

Why don't one of you guys take an old recoil spring, cut a piece of it and start flexing it to actually see if it gets weaker? My bet is that it won't.
Or, actually measure the resistive force of one compared to a new one. Spring length doesn't have much to do with the resistive force, just the "throw" of the spring.

[JohnKSa]

For those of you that replace recoil springs for a preventative measure, do you do the same thing for rifles?

Most rifles aren't recoil operated, so it's not quite an apples-to-apples comparison.

I tend to replace parts preventively based either on manufacturer recommendations or recommendations of advice from people with enough experience to be credible--gunsmiths, high-volume competitors, etc. or based on my own experience.

What about striker, extractor, and ejector springs?

If they're on the list of parts that the manufacturer recommends replacing periodically then yes. If not, they get checked periodically for proper function and replaced if they wear out or break. And if I notice a pattern in terms of how long it takes them to wear out or break then they will get replaced periodically at an interval shorter than the time I've observed it typically takes them to wear out or break.

Why don't one of you guys take an old recoil spring, cut a piece of it and start flexing it to actually see if it gets weaker?

I've repeatedly provided a link on this forum and others to test results showing that compressing springs can eventually cause them to weaken.

If you think the results of the test are questionable, you could replicate it yourself to see if your results are counter to the results obtained by the experimenter.

http://thefiringline.com/forums/show...7&postcount=44

http://www.network54.com/Forum/79537...'s+a+test-

[Bill DeShivs]

John,
MY results are absolutely contradictory. My real experience is with high carbon steel. I have made 4-5000 leaf springs, and examined thousands more. I have never seen one weaken. This is why this subject is important to me. My experience is that these springs work harden and break, not weaken.

[JohnKSa]

I have made 4-5000 leaf springs, and examined thousands more. I have never seen one weaken.

Recoil springs tend to be coil springs, not leaf springs. Ignoring that, for the moment, I'm interested to know more about your approach to examining springs.

• What methods are you using to measure the strength of the spring and in what units do you typically record the spring strengths of the springs you examine?
• Do you typically record measurements of spring strength at the time of manufacture to establish a control for later measurements?
• How long do you typically wait between spring strength measurements (measured in time or cycles, whichever you prefer)?
• Do you note any variation at all in the strength of a spring over its lifetime or does it simply break without any warning?
• What's the longest interval (or most number of cycles) elapsed between an initial spring strength measurement you've made and a spring strength measurement made later in the life of the spring?

[Bill DeShivs]

Well, according to your questions my methods are very crude. I restore antique switchblade knives. As each spring is hand made and custom fitted, I don't measure spring strength, but I could certainly tell if one was weakened-and my customers would surely notice. They pay very good money to have my work done. I have had no complaints about spring strength. Zero complaints.

I have examined 150 year old knives that had springs that were like new-any stronger and they would have ruined the mechanisms.

I have noticed no variations in spring strength until immediately before breakage (one-two cycles.)

Coil springs tend to have less acute loading than a dedicated leaf, so my assumption is that they would be even more durable.

This is why I'm argumentative about springs. My considerable experience with springs (and guns) tells me there is something very wrong with all this spring changing going on. I understand some guns may be designed with expendable springs.

But, I can not understand high carbon steel springs weakening-without overheating, over compression, or rusting. Perhaps the speed of compression has something to do with it-that's the only thing I have no knowledge of.

[Gary Wells]

Recoil springs do weaken, I have had personal experience with this issue with a couple of my .45 autos.

[Walt Sherrill]

Springs, coiled and used in mags and recoil applications seem, at least to some of us, to be quite different from knife springs.

We've been through this before, in lengthy discussions here on TFL, Bill, and you've participated in those discussions. A couple of folks provided pretty extensive documentation and proofs in those earlier discussions, and there's been quite a bit already provided in this message chain.

It would seem to me that the kind of springs you make are dynamically different than the springs we're talking about: they seem to function differently. And, unlike magazine springs aren't expected to be kept compressed at high levels for extended periods under great loads. I think even recoil springs must flex in more ways than a knife spring, twisting as they are compressed.

I don't doubt your experience with knife springs, but am not sure that the springs you are most familiar with are all that similar to recoil or magazine springs in how they are made, how they work, or how they are stressed.

You mention over-compression. Over-compression may be the issue -- as it seems that with some guns, especially compacts, "over-compression" may now be a part of some guns' normal operating mode -- necessary to get the guns' to do what must be done, given their smaller size.

If that is so, the springs, in some guns, have become expendable components, just like bullets. In other weapons, it's not an issue. But springs do sometimes give up the ghost. Springs that are stressed less seem to last much, much longer.

Most of the sub-compact and compact .45 gun makers recommend changing out recoil springs in their smaller guns at a much lower round count than with their full-size guns. Why do you think that might be? Early on, when we first started this discussion, a year or so ago, you would have said "inferior design" or "inferior materials" -- as anybody knows that springs should last forever.

In the case of these smaller guns, it might be that we've pushed the envelope for spring steel about as far as it can be pushed, right now, and for the new smaller guns, there's not enough "spring" there to do the job...

I think you continue to compare apples to oranges (when talking about recoil/mag springs vs. knife springs) and are trying to tell us that just because they're both fruit (i.e., springs), that's is all that matters. You seem to be saying that the type of spring, and how it's used and must deal with loads, doesn't really make a difference. Springs are just springs. Maybe. Maybe not.

You are free to convince us otherwise, however.


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[45Gunner]

I'm not an engineer but from what I understand about springs is that while they are at rest, they are not "wearing out", regardless of whether they are under tension or not. It is the working of the spring, or put another way, the contraction and expansion that weakens the spring over time.

As I have stated previously, I shoot several thousand rounds per month, mostly utilizing 1911's. I know my guns and I can feel when the slide is not cycling with the power it should have and that is backed up by where the spent casings land when ejected. If I do nothing, I soon begin to have various feed failures.

Recognizing that this happens over time, I elect to change my recoil springs on a schedule and at the same time change the firing pin spring simply because Wolff includes a firing pin spring in the package with the recoil spring. No reason not to change a spring if it is provided. Once new springs are put into my 1911, the old "snap" comes back and makes the gun feel the same way it did when it was new. My carry gun gets shot frequently and because it is a carry gun, its reliability must be unquestionable. It is for that reason I change springs as a preventative maintenance item instead of waiting for one to fail.

As far as the post about knives with 150 year old springs that still feel new, it just goes to further prove the point that springs do not wear out at rest. It is the constant working of the springs that cause them to weaken.

Further, I have about 50 magazines that I keep loaded. They alternate between my safe and range bag. I have never had a magazine spring simply wear out from being compressed. Again, they were not doing any work.

[Scimmia]

MY results are absolutely contradictory. My real experience is with high carbon steel. I have made 4-5000 leaf springs, and examined thousands more. I have never seen one weaken. This is why this subject is important to me. My experience is that these springs work harden and break, not weaken.

If we're going to look at other appplications, let's look at a very common real world application of coil springs: the suspension of a car. How many 10-20 year old cars to you see driving around with their rear sitting way too low? What exactly do you think causes this?

[Walt Sherrill]

Wolff Springs, in their FAQ area, suggests ways of prolonging spring life. (Telling you how to prolong spring life is not a good way to sell more springs, by the way...)

They say that springs tend to do well until pushed to or beyond their elastic limits -- the maximum limit for which they were designed. That's why they suggest downloading hi-cap mags a round or two if they're being stored LOADED, and ditto for mags in sub-compact guns. I think that's why that old mag full of .45 rounds from WWII will still work properly when put in Grandpa's gun -- the springs, while under load, were loaded below their design limit.

I used to think that working springs was what wore them out, but after a lot of discussions and reading, I realize that just working a spring may not cause that much wear, if you work them in ways for which they were designed, and not in ways that push them to or beyond their functional limit.

I think that's why valve lifter (tappet) springs tend to last so darned long, despite millions of cycles -- they are well designed for their application, and it's hard to push them beyond that limit. (If you're able to stretch them or compress THAT far -- beyond their design limit -- you're probably going to damage a valve or lifter, too!)

Wire coiled recoil springs are complex: they are often designed to bend AND twist. It would seem that knife springs tend to flex along one axis, while coil springs may do more. Magazine springs are arguably more complex than recoil springs -- with flat straight segments and curved ends -- also flexing and twisting as they function. That simple piece of metal has to do a lot!

Bill talks about leaf springs that last forever, in knives and cars. I've had leaf springs fail in a car more than once. They just quit holding up the car. I've seen a few break, too. I've also had a car rear coil spring break, and had another one that sagged. (A '66 Pontiac in early 1970!)

When someone tells me that his 1911 mags have worked for years without problems, I don't doubt him. When he tells me his 17 round double-stack mag springs have the same performance history I'll be a bit more skeptical.

[johnbt]

"I like Wilson's philosophy regarding recoil spring selection which seems to be that the the distance that spent cases are thrown / discarded is only a part of the picture."

Of course. It's a machine, a system. But the thread is about recoil springs.

[Bill DeShivs]

Scimmia-
Overloading, period.

Walt-
These springs are designed to be kept under compression indefinitely, and they are under more stress than any recoil or magazine spring. They are more akin to an S&W "K" mainspring, under more load.
And-springs are springs.

Please understand, I'm speaking only of high carbon steel springs, not 17-7ph, or 303, etc.

[Walt Sherrill]

These springs are designed to be kept under compression indefinitely, and they are under more stress than any recoil or magazine spring. They are more akin to an S&W "K" mainspring, under more load.

And you base the statement (underlined above) upon what facts in evidence, empirical measurements, or testing methods? How do you know its MORE STRESS? But, let's put that point aside for a minute...

If Wolff is correct in their FAQ and you've built your knife springs properly, you've built them to function within their design limits, then any stress they have to deal with is not likely to cause problems. The fact that the compression is constant is actually irrelevant -- if at it's greatest, it meets your design requirements.

When you start to open one of your knives, aren't you then putting a little additional stress on the spring, too -- at least momentarily? I'll bet you've built in extra strength into the spring for that brief exercise, as well. Opening and closing that knife thousands of times might put accelerate wear a bit, but I'll bet you've designed for that, too.

We already know that a 1911 mag spring can be kept under full compression for decades without problems. What's the difference between THAT 1911 mag spring and your knife springs?

And, what's the difference between your knife springs and the springs in a compact Wilson 1911 -- which Wilson recommends being changed out much more frequently than in a full-size gun?


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[chack]

Originally Posted by chack

For those of you that replace recoil springs for a preventative measure, do you do the same thing for rifles?

What about striker, extractor, and ejector springs?

Why or why not?

I'm still curious about this. No one has commented yet.

[Walt Sherrill]

What about striker, extractor, and ejector springs?

Why or why not?

Never had one of those other springs fail. Have you?

Ooops. Did have a problem with a weak CZ extractor spring, some years back, before they went to stronger springs.

When you buy from Wolff, you get a new firing pin spring with each recoil spring, but I seldom change them out.

Some recoil springs seems to work harder than most other springs. Except, maybe, for some mag springs.

[Scimmia]

For those of you that replace recoil springs for a preventative measure, do you do the same thing for rifles?

What about striker, extractor, and ejector springs?

Why or why not?

There is a difference there. As the recoil spring weakens, it will change how recoil is percieved, but until it gets really bad, the gun will continue to function. For the extractor or striker, it either works or it doesn't. If it doesn't, it's time to replace it. If it does, there's nothing to gain from replacement. The exception is when I buy a used gun of unknown provenance, in that case, I replace most of the function springs immediately.

Scimmia-
Overloading, period.

Unless the springs are overloaded from the factory with nothing in the trunk or rear seat, that's complete bull.

[Bill DeShivs]

Gee, Walt-you can simply feel the pressure upon closing the knife!
Opening an automatic knife doesn't put any additional stress on the spring.
I agree that subcompact guns may be designed to over stress springs. My springs, by design, can not be over compressed. As far as I can tell, that (and possibly Wilson's materials) are the only differences.

Scimmia-why don't they ALL fail? And why don't carmakers recommend replacement? How do you know they have not been overloaded?

[JohnKSa]

Originally Posted by chack

I'm still curious about this. No one has commented yet.

See post #53.

...why don't they ALL fail? And why don't carmakers recommend replacement?

Not all cars are the same, not all cars are used under the same conditions, not all cars are used as much/are driven as many miles, and not all springs are created equal.

There are recommendations made as to when to replace suspension springs.

http://hardlymoving.hubpages.com/hub...ng-Replacement

" Consider replacing the rear coil springs if the car tends to 'bottom out' when passengers are seated in the rear or the trunk is filled with moderately heavy cargo."

http://www.performancesuspension.com...f-springs.html

"Springs wear out from use and cause lowered ride height, sagging along with poor control and ride quality."

http://www.crxsi.com/info/alignment/...ide-Height.htm

"If the suspension stops show evidence of bottoming, and/or the coils on coil springs have been contacting one another, the springs may need replacing."

http://www.northwestoffroad.com/parts/2stage.php

"replacement springs have been designed to replace the original factory springs which fatigue and lose ride height quickly. "

http://www.aa1car.com/library/ride2h.htm

"If only one spring is sagging, most experts recommend replacing both springs on an axle to maintain even side-to-side ride height."

http://www.springworks.com/faq.html

"WHEN do leaf springs need to be replaced?
There is no standard life expectancy for leaf springs. In general, leaf springs on smaller lighter weight vehicles tend to last longer then leaf springs on heavier full-sized vehicles applications. To determine when coil springs need to be replaced have the springs inspected and the vehicle ride height checked by a trained professional."

This is why I'm argumentative about springs. My considerable experience with springs (and guns) tells me there is something very wrong with all this spring changing going on. I understand some guns may be designed with expendable springs.

I provided the results of careful measurements made in a controlled experiment that support the fact that coil springs do weaken with use. You admit that you have no careful measurements to stack up against the experimental results but apparently believe that your assessment of leaf spring weight made by feel is sufficient "evidence" to dismiss those careful measurements in spite of the fact that others have replicated the experiment and corroborated the results that you reject.

I provided a technical article discussing spring weakening in car suspensions and methods to minimize/prevent it via different manufacturing techniques. You still maintain that car suspension springs won't weaken unless overloaded but provide no corroborating evidence or citations.

I provided a technical article discussing the problem spring fatigue and "relaxation"/weakening. You still maintain that springs don't weaken, they either stay good or break but you don't provide any citations or technical articles to support your point.

Several gun makers provide recommendations for coil spring replacements at intervals or at the least recommend testing coil springs at intervals to insure they haven't weakened to the point of needing replacements. In addition, we have a noted coil spring maker that also indicates that coil springs can weaken and need to be replaced but you discount their recommendations and cautions based on nothing more than your opinion and experience with leaf springs.

Several folks have chimed in to note that their recoil springs have weakened and they've had to replace them but you ignore their claims.

At this point there's not really any remaining question that coil springs can and do weaken from use nor that in at least certain circumstances periodic replacement is prudent. There's sufficient experimental evidence, technical evidence, experiential evidence, manufacturer recommendations, spring maker advice, etc. to support the assertion beyond a shadow of a doubt.

[Bill DeShivs]

John,
My purpose is not to be argumentative.
Nor are my methods scientific.
Obviously some springs fail, but I have not seen it, except as I noted. I certainly don't understand why.
If springs get weak, how weak will they get? Will they completely collapse?
Here is a very simple experiment to understand why I say this:
Take a piece of steel wire (spring wire, if you have it,)and bend it repeatedly in the same spot. Tell me if it gets noticeably weaker, or if it breaks.

[OJ]

Dunno if it was needed but a couple of years ago on my Colt's Government Model Series 70 - made in 1970 - the slide stop slid down locking up the action at the range.

Checked with Wolff Springs for a stronger - well at least newer - firing pin spring - found they had a package deal that included both recoil spring and firing pin spring - well - you know how things like that go - I ended up buying two of those. Original had over 7K rounds through it and the repro over 5K. I guess my long life as a surgeon led to to view it as "preventive medicine" -

At any rate, the new ones initially had about two coil length over the used ones - but still 30 coils. They are the same length now. No further problems. Dunno if it was needed but, didn't hurt.

[Scubasimmons]

It's called creep. Keep a spring in a compressed state and it will get 'weaker'. Most of the spring we are talking about are linear so the force they exert is proportional to their deflection. When a spring is stored under compression it will creep (it's a fact) and will not exert the same force.

[Bill DeShivs]

And here is an article that says it doesn't happen:
http://findarticles.com/p/articles/m...7/ai_99130369/

[Walt Sherrill]

That article isn't worth warm spit. No explanations. No tests. No nothing except opinion. And, I've made the point, more than once -- in these discussions -- that springs don't mend with rest -- so that writer is wrong twice over.

The only reason to rotate mags is to spread the wear over a larger number of mag springs. Seems like a false economy, to me. And some of the experts explain that if you've got hi-cap mags, leaving them FULLY LOADED will accelerate their decline. Download a round or two, and there's hardly any load or stress (or wear.)

I've had SOME springs fail -- more often magazine springs in hi-caps and compacts than anything else. My posting that fact HERE carries the same weight as the article you cited. (And, by "fail," I mean the springs caused the gun to malfunction -- they didn't break but the gun didn't work right. Upon replacement, the gun worked right again.)

With the last set of mag springs I had to replace, it was springs for a bunch of compact mags for a Kahr P9; the old springs (factory) were so soft, loading rounds was easy. They were also so soft they wouldn't always properly lift the next round high enough to be caught by the slide and chambered.

The replacement springs were so damned stiff I had a terrible time installing them, and almost needed a bumper jack to load the mags. (More than one flew off across the room as it slipped from my grasp.) I sold that gun soon after replacing th mag springs, after testing the springs for proper function in the gun. I'm sure they'll take a "set" as with Glock mags, and become easier to load over a relatively short period. If not, there are mag loaders for the hard-to-load mags. I could load them by hand, but it wasn't easy.

I'm not sure I believe your claim that all springs are the same (i.e., "springs are springs.") That's a bit like saying, "guns are guns.")

When you've successfully made some magazine springs for a high-cap mag that lasts as long as good quality knife springs, your opinion on the subject of recoil and mag springs will be more credible. They should last forever, according to your experience.

But, as long as you offer only opinion and anecdotal evidence based on your experience with leaf springs used in knives, things won't progress.

[10mm4ever]

I dont see why some cant fathom why springs weaken. Take ANY piece of metal, keep on flexing it and see what happens! Everytime you change the molecular structure of metal, you weaken it. Granted, spring steel takes longer for this weakness to occur, but eventually it does! This is why keeping a spring compressed for extended periods doesnt have the same effect as the continual flexing does.