View Full Version : Spring debate update 2010!
Perhaps the oldest debate regarding guns on the net, needs to be updated! :cool:
One school of thought (i'd call it the 'old school') is that compressed springs in mags, guns left in condition one, etc., will lose their tension from being left compressed for long periods.
Te other school (i'd call it 'new school') states that springs lose their tension by repeated compression and release, and leaving springs compressed - especially with the quality of modern springs - is a non issue. Guns, mags, etc can be left loaded more or less forever.
anecdotally, we hear of people finding some gun left loaded for 20 + years and working fine.
Personally, I have kept a CCW 1911 in condition one for years, occasionally changing mags when it occurred to me, and it had no impact in reliability of that gun.
People here leave their striker fired guns (glock, MnP, etc) in condition one for years on end? What's the 2010 updated status of this old 'debate'?
The old is the new, in the engineering world (as I know it and have been taught), there never was this idea that springs wore down as they were stored.
What this means if the mag is loaded within the range of the spring, it is acceptable and will not wear. The spring has to do work to degrade. Since work is a function of force and distance, we limit the distance by stuffing the mag full. It does work when it is loaded (it compresses) and that is it.
Most guys in my department leave their guns loaded constantly never changing out mags because they only have the 3 they were issued. They do however change out the ammo once per year when new ammo is issued and they have to qualify again.
A few of them also practice regularly but again only have the 3 mags they were issued. These folks constantly change out the issue ammo for practice ammo and shoot a lot at the range.
Neither side seems to have issues. It has been that way for a few years, whether it was the issue berettas or now the issue glocks. Honestly I don't think either side is right and mags have and/or will fail and people want something to blame it on.
Personally I would feel fine leaving a mag loaded for 60 years and using it, the only thing I would be worried about is ammo failure.
The old is the new, in the engineering world (as I know it and have been taught), there never was this idea that springs wore down as they were stored.
What this means if the mag is loaded within the range of the spring, it is acceptable and will not wear. The spring has to do work to degrade. Since work is a function of force and distance, we limit the distance by stuffing the mag full. It does work when it is loaded (it compresses) and that is it.
That would then apply to springs inside guns etc vs just mags no doubt, just to clarify.
Alpha Sierra
08-17-10, 12:07
Springs do not wear from static loads. They take an initial set then degrade over time from cyclical loads.
There is no debate. Period. End of story.
That would then apply to springs inside guns etc vs just mags no doubt, just to clarify.
Correct, all springs, tension and compression. Work is work, it wears springs. If it moves something it is work, if it is compressed or pulled tight, it is stationary, thus not wearing down on the spring.
There are of course other environmental factors that will cause the spring to fatigue/degrade, but for the purpose of this topic, you are not causing harm.
Think about the hammer springs or striker springs, people will refuse to store loaded mags but carry a 1911 cocked and locked for 99% of the guns life.
Springs do not wear from static loads. They take an initial set then degrade over time from cyclical loads.
There is no debate. Period. End of story.
It's all good brother, just wanted the updated info just in case. :neo:
Correct, all springs, tension and compression. Work is work, it wears springs. If it moves something it is work, if it is compressed or pulled tight, it is stationary, thus not wearing down on the spring.
There are of course other environmental factors that will cause the spring to fatigue/degrade, but for the purpose of this topic, you are not causing harm.
Think about the hammer springs or striker springs, people will refuse to store loaded mags but carry a 1911 cocked and locked for 99% of the guns life.
Amazingly, it's a Q/debate I still see on some boards.
Alpha Sierra
08-17-10, 12:34
Amazingly, it's a Q/debate I still see on some boards.
There's a lot of dumb stuff being debated on the errornet by people way outside their lane.
Thomas M-4
08-17-10, 14:34
Only time I have had spring problems were with 40-60+ year old milsurp and heavily used modern firearms or cheap clones. The cheap clones well they had cheap shitty springs. Use good springs never had a problem and just replace them when they are wear out.
RAM Engineer
08-17-10, 14:47
One school of thought (i'd call it the 'old school') is that compressed springs in mags, guns left in condition one, etc., will lose their tension from being left compressed for long periods.
Te other school (i'd call it 'new school') states that springs lose their tension by repeated compression and release, and leaving springs compressed - especially with the quality of modern springs - is a non issue. Guns, mags, etc can be left loaded more or less forever.
I call it the "doesn't know anything about material properties, engineering, or science School"
vs. the
"correct school"
Alpha Sierra
08-17-10, 17:35
I call it the "doesn't know anything about material properties, engineering, or science School"
vs. the
"correct school"
How did I miss that?
Will, the "old school" that you refer to are the people I was talking about as being WAY the hell out of their lane.
The "old school" is the correct school.
Material science has been replaced by the errornet.
JacksonDavion
08-17-10, 18:02
We've discussed this at work before (I'm fortunate enough to work with like-minded engineers) and we all agree we've never heard another engineer/scientist/technician vouch for the "old school" static compression spring failure idea.
There's a lot of dumb stuff being debated on the errornet by people way outside their lane.
Lord how I know that...:rolleyes::D:rolleyes:
Yup, no such thing...... Never happens...... Everyone knows.... Trust me....
"The phenomenon of stress relaxation, the time decrease of internal stress due to localized flow in a solid under constant uniaxial strain......"
"This decay of contact force, a natural consequence of the structure of all metals, is called stress relaxation. Stress relaxation is the time dependent decrease of the stress in a metal under constant strain, such as in a beam with fixed deflection. (The metallurgical processes are similar to those that cause the related phenomenon called creep, where the metal changes geometry over time under a constant stress.)"
Gun and spring engineers/designers take this stuff into account. That makes our lives simpler.
I'm a civil engineer, but not too good at metallurgy...
In theory, if the spring is in its elastic range (where it should be designed), it should not experiment an initial "set", but we all know the magazine springs do take a set quite early and hopefully stay there for a long time. Less stressed springs like the 7 round for a full size 1911 may not even take an initial set, and last a long time. The springs in hi-cap IPSC guns where they try to stuff as many rounds as possible don't last long.
And QC is very important, some springs last a long time, others (sometimes of the same brand) don't. Obviously the material is not the same, or some manufacturing details were different.
The recoil springs slowly take a set with extended use. If the design is not very conservative (as in small 1911s, officers and smaller) they last VERY little, manufacturers recomend replacement at 500 rounds!
The mainspring is most pistols last forever because the space available for them is generous and they compress very little, so you can design very conservatively. So cocked and locked is not an issue.
JacksonDavion
08-17-10, 19:11
A modern spring that is manufactured/heat treated properly and compressed appropriately without cycling shouldn't experience enough stress relaxation for it to become a failure mode. Obviously if you do something weird like hold it at a high temperature this would no longer be true. I wasn't trying to imply that nothing was happening to the spring, only that its not an issue without outside factors.
Tiro-Fijo has covered the last line of my previous post well.
The "initial set" that people talk about however is a misunderstanding of the mechanics involved. Stress relaxation is a time based phenomena proportional to the stress level. When a spring is new, and long, it experiences a higher stress on installation and compression then it does later in life. Therefore, the rate of stress relaxation is greater when the spring is new, because it is new. Stress relaxation continues however at an ever decreasing rate. The stress level and associated load that pushes the rounds up in the magazine continually decreases over time. Graphically it is a decreasing slope curve that asymptotically approaches zero.
When a magazine spring begins causing feed failures, it has simply experienced too much time, at too high a stress level to produce a load sufficient to lift the round fully before the slide passes by. That gets into an F=MA discussion, and I am done for the evening....
to add to the debate I've been around pistols for thirty or so years to include competitive use for about 20 and only in the last 5 years or so have I heard a bunch of talk especially with 1911's but also with aothers to replace recoil springs every x # of rounds. I shot the same 1911 in competition with about 40k on the same springs with no functioning or gun damage issues. What gives?
I even have seen comments that is consdidered routine to replace recoil sping in glocks at 5k, even though you see the article about Chuck taylors 200k+ glock 17 that is still going strong.
When we turn our rifles in to the armory, the armorers will put them on 'semi' and dry fire them to "release the compression on the trigger spring." I tell them they're not helping, certainly not by handing out rifles that are off safe, but no one listens.
CAVDOC, I think lately the manufacturers just want to play it very safe when they suggest the recoil spring replacement intervals. People shoot more than in the old days and sometimes think the guns and parts/springs should last forever or it is garbage, not so.
If you make a spring tester, you can check your recoil spring (new or used) instead of guessing with hand cycling or where the empties land:
http://www.realguns.com/Commentary/comar16.htm
Sometimes the springs last a looong time, and sometimes they die early. And some guns are very forgiving of recoil spring variations while other are much more sensitive. A pistol that has enough barrel+slide mass to produce a moderate slide velocity with a given load/caliber, and has enough size for a decently sized recoil spring is always going to be easier on it, and more forgiving of the magazine spring strength.
Doc Safari
05-09-11, 16:02
Yup, no such thing...... Never happens...... Everyone knows.... Trust me....
"The phenomenon of stress relaxation, the time decrease of internal stress due to localized flow in a solid under constant uniaxial strain......"
"This decay of contact force, a natural consequence of the structure of all metals, is called stress relaxation. Stress relaxation is the time dependent decrease of the stress in a metal under constant strain, such as in a beam with fixed deflection. (The metallurgical processes are similar to those that cause the related phenomenon called creep, where the metal changes geometry over time under a constant stress.)"
Gun and spring engineers/designers take this stuff into account. That makes our lives simpler.
So, if I am reading this and the other posts correctly, a spring at rest won't fatigue and fail, right?
When MagPul puts the following phrase in their MOE stock advertisement: "The extra-power lock mechanism uses a premium chrome-silicon spring to avert auto-collapse failure and maintains strength by resisting spring relaxation. ", what they are referring to is failure from use, correct?
Theoretically, if you had two identical rifles with this MOE stock and one was used extensively while the other stayed in the rack, then the one in the rack would not experience the failure but the one in use would? Right?
(I know that's an AR carbine part and not a handgun part).
Similarly, on take two identical handguns, the one in the rack likely would never need a new recoil spring while the one in use would need one due to the "work" being put on it, correct?
Nephrology
05-09-11, 16:37
Springs do not wear from static loads. They take an initial set then degrade over time from cyclical loads.
There is no debate. Period. End of story.
Unless my intro physics class lied to me, then this is exactly the case.
No debate here.
You guys are mixing up fatigue failures and stress relaxation.
An unfired, but installed recoil spring has just spent less time at a high strain level than one that has been fired a bunch.
Releasing the trigger on a weapon that is to be stored for a long time does in fact extend the life of the spring, because it is spending less time at a condition of high strain (which produces high stress). Stress relaxation is proportionate to the strain.
Do you recall reading LAV's suggestion to lock the slide back for a week on the the GEN4 Glocks to reduce the spring force? That works because the spring is sitting at a higher stress state for an extended duration.
If you load Glock 17 mag with 13 or 14 rounds, and leave it in a drawer for 10 years, there is a greater chance of it feeding the last round and locking the slide back than one loaded with 17 rounds and left for the same period, all other parameters being equal. If you disassemble both mags after those ten years, the one that has been loaded with 17 rounds will have a spring that is shorter than the one loaded with 13 rounds. That shorter spring will produce less force on the follower than the longer one.
I bet most of us have a magazine that has been loaded for a long time and not used..... take it apart and compare the spring length to a new unloaded mag spring.
I have a Glock 26 that's been loaded since '09.
I hate shooting that little gun, but I am pretty confident in the springs.
So, if I am reading this and the other posts correctly, a spring at rest won't fatigue and fail, right?
When MagPul puts the following phrase in their MOE stock advertisement: "The extra-power lock mechanism uses a premium chrome-silicon spring to avert auto-collapse failure and maintains strength by resisting spring relaxation. ", what they are referring to is failure from use, correct?
Theoretically, if you had two identical rifles with this MOE stock and one was used extensively while the other stayed in the rack, then the one in the rack would not experience the failure but the one in use would? Right?
(I know that's an AR carbine part and not a handgun part).
Similarly, on take two identical handguns, the one in the rack likely would never need a new recoil spring while the one in use would need one due to the "work" being put on it, correct?
Fatigue is a function of cyclical loading. If there is no cyclical load there is no fatigue by definition.
Your question depends on factors not included in the question. There are more modes of failure than just fatigue. The one left on the rack would not fail from regular mechanical fatigue though.
Doc Safari
05-10-11, 08:44
Fatigue is a function of cyclical loading. If there is no cyclical load there is no fatigue by definition.
Your question depends on factors not included in the question. There are more modes of failure than just fatigue. The one left on the rack would not fail from regular mechanical fatigue though.
We all know the guy that buys an old mint condition World War II era 1911 or something, and the first thing he does is replace all the springs even though the gun looks brand new.
Necessary?
Similarly, if you have AR carbines in the rack resting on the buttstock, is the spring in the stock going to eventually fail from factors other than mechanical fatigue?
lightsareout
05-10-11, 12:04
A car sits on its springs and compresses them constantly. It by no means shortens the life of the springs. I don't see why it would be any different with springs in the gun world.
much depends on the load of the spring. metals go through elastic and plastic deformation. If you enter a high enough load you will deform the spring. If the load is light enough then the spring will return to its original shape. There is also the factor of metal creep under a constant loading.
Long story short. put your springs in the lowest cmpression possible to extend their lives. It may only be a small difference (possibly undetectable) but it is real.
I am a professional metallurgist
We all know the guy that buys an old mint condition World War II era 1911 or something, and the first thing he does is replace all the springs even though the gun looks brand new.
Necessary?
Similarly, if you have AR carbines in the rack resting on the buttstock, is the spring in the stock going to eventually fail from factors other than mechanical fatigue?
If it has been stored at room temperature and there was nothing wrong with the springs to start with it might be fine, but it will definitely not be as good as new. This is not exactly my area so couldn't say exactly how long X spring will last at Y load. I do know spring companies will give you charts with the stress relaxation info on their products.
Well, when I said 'other modes of failure' I was thinking of creep or stress relaxation as TXBob pointed out. There is also of course corrosion and thermal shock which can eventually happen.
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