View Full Version : Whats the best way to prevent your magazine from loosing tension
pbmaster2k89
11-04-12, 15:40
I was wondering how could keep the spring in my Sig 226 magazine from loosing tension which causes a round to not feed. Obviously we want to keep our magazine and handgun loaded at all times so its ready for use in a life or death situation, but of course keeping the mag loaded all the time makes the spring loose. How can i prevent this?
Downloading by 10% to 20% for any mags not needing to be topped up will dramatically extend the spring life. Even then, and especially for ones fully loaded you should routinely replace the springs. Note that some companies design more for long service life over maximum capacity (i.e. HK) and allow greater time between spring swaps.
This is just basic preventative maintenance.
Springs are cheap, magazines are consumable items. Use them, rebuild them, or replace them, and move on.
How can i prevent this?
The only way I know to fully prevent it is to not use the magazine.
Springs wear out eventually.
pbmaster2k89
11-04-12, 16:37
I figured as much cause even though i have a 15 round mag, i only load 10. I guess ill jus keep replacing them
I was wondering how could keep the spring in my Sig 226 magazine from loosing tension which causes a round to not feed. Obviously we want to keep our magazine and handgun loaded at all times so its ready for use in a life or death situation, but of course keeping the mag loaded all the time makes the spring loose. How can i prevent this?
I have left several SIG 226 and 220 magazines left loaded for extended periods (more than 3-4 years) and experienced no problems.
If spring tension is a concern, then I would recommend replacing the factory mag springs with Wolf brand springs. They work very well and will hold-up better than the factory spring.
Dos Cylindros
11-04-12, 16:44
It is a misconception that leaving the mag fully loaded weakens the spring. It is the cycling of the spring that wears it out. With that out of the way, you should still periodically replace your mag springs as a part of general upkeep.
Failure2Stop
11-04-12, 16:46
It is a misconception that leaving the mag fully loaded weakens the spring. It is the cycling of the spring that wears it out. With that out of the way, you should still periodically replace your mag springs as a part of general upkeep.
This.
Keeping a mag loaded does nothing to weaken it. Springs weaken when going from loaded to unloaded, not loaded with bullets, loaded with tension. The act of using it is what causes a spring to weaken.
The only way to make your mag spring not weaken is to never use your gun. Lol
Springs are cheap, magazines are consumable items. Use them, rebuild them, or replace them, and move on.
It is a misconception that leaving the mag fully loaded weakens the spring. It is the cycling of the spring that wears it out. With that out of the way, you should still periodically replace your mag springs as a part of general upkeep.
^ Agree w/ Above. Spot on.
I figured as much cause even though i have a 15 round mag, i only load 10. I guess ill jus keep replacing them
^ imho: Load them to spec.
- The extra 5 rounds in a 15 is A LOT, especially with a spare mag. 11+10 = 21 Total vs 16+15 = 31, I'll take the greater.
I figured as much cause even though i have a 15 round mag, i only load 10. I guess ill jus keep replacing them
Very unnecessary
Toyoland66
11-04-12, 18:32
I was wondering how could keep the spring in my Sig 226 magazine from loosing tension which causes a round to not feed.
Is this an actual or theoretical problem? If you are having this issue, change the mag springs, otherwise carry on and don't worry about it.
Is this an actual or theoretical problem? If you are having this issue, change the mag springs, otherwise carry on and don't worry about it.
Exactly. If you are having problems then change the springs but if you are just worried about it put your mind at ease. My P226 duty mags have been essentially constantly loaded for about 8 years now with no issues. And with probably 10-15k rounds of loading/unloading during that time (I guess it wouldn't hurt for me to change them preemptively but they haven't had any issues).
It is a misconception that leaving the mag fully loaded weakens the spring. It is the cycling of the spring that wears it out. With that out of the way, you should still periodically replace your mag springs as a part of general upkeep.
Google stress relaxation in metals.......
It is a corollary to creep. Creep is movement along grain boundaries due to constant load, stress relaxation is movement along grain boundaries caused by a displacement, resulting in progressively lower stress (the material relieves the strain by shifting along grain boundaries).
This is a stress and time based phenomena.
The stress on the magazine spring is created by compression. The rate of relaxation increases with increasing stress levels. Decreasing the compression decreases the maximum stress experienced, extending useful life.
Note that some designs are more susceptible than others based on design goals.
The physical manifestation of this is that a magazine spring left loaded for an extended period of time will be shorter than a new one.
That reduction in length is proportional to a reduction in force.
This is really, really easy to prove. Take a Glock magazine that has been fully loaded for 6 months or more, disassemble it and compare the spring to a new one. It may still function, but that loss of length represents a loss of design margin.
Google stress relaxation in metals.......
It is a corollary to creep. Creep is movement along grain boundaries due to constant load, stress relaxation is movement along grain boundaries caused by a displacement, resulting in progressively lower stress (the material relieves the strain by shifting along grain boundaries).
This is a stress and time based phenomena.
The stress on the magazine spring is created by compression. The rate of relaxation increases with increasing stress levels. Decreasing the compression decreases the maximum stress experienced, extending useful life.
Note that some designs are more susceptible than others based on design goals.
The physical manifestation of this is that a magazine spring left loaded for an extended period of time will be shorter than a new one.
That reduction in length is proportional to a reduction in force.
This is really, really easy to prove. Take a Glock magazine that has been fully loaded for 6 months or more, disassemble it and compare the spring to a new one. It may still function, but that loss of length represents a loss of design margin.
As a rule springs wear due to number of cycles of compression (or tension or torsion etc). The number of cycles could be hundreds, thousands, or millions depending on the design. To say that all springs will fail due to continued loading as a rule is not quite as accurate. How often do you have to replace coil springs or leaf springs on a vehicle? Pretty much never if they were properly designed. Same thing on a magazine spring. If it is properly designed it will not fail due to continued loading, if it is not it will eventually loose tension. So to say that it will experience creep or take a set or whatever you would have to be pretty specific about the exact magazine and spring.
Don't overthink this.
Load to capacity. The manufacturer designed it that way. Shoot the gun. When the mag bobbles or the spring will not lift the follower enough to engage the slide stop, replace the spring.
That's all.
Magazine springs are a lot more stressed than coils springs in engine valves or leaf springs in a vehicle. They are not designed to last forever.
And as spr1 said, they take an initial set.
Not all mag springs have the same design, and some designs are less durable than others. The QC of the springs is also variable, and not all springs last the same, even from reputable makers.
You can theoretically reduce stress and enhance spring life by downloading, but how much is arguable, and of course you are losing valuable rounds.
I think it is much better to just live with it, and replace springs when necessary. Some mags loaded to full capacity are more finicky to insert with a closed slide, and in this case I prefer to download one round.
Dos Cylindros
11-06-12, 07:41
[QUOTE=TiroFijo;1434651]Magazine springs are a lot more stressed than coils springs in engine valves or leaf springs in a vehicle.QUOTE]
I seriously doubt that. The force placed on valve or leafe springs is probably an order of magnitude greater than that placed on any magazine spring. Valve springs are cycled at an astounding rate that would boggle the mind if anyone actually bothered to do the math. Leaf springs store and return more kenetic energy that any mag spring will ever be subjected to. I am not a physics major, but I do know how much a car/truck weighs and works. There is no way a mag spring is under more strees than a valve or leaf spring.
[QUOTE=TiroFijo;1434651]Magazine springs are a lot more stressed than coils springs in engine valves or leaf springs in a vehicle.QUOTE]
I seriously doubt that. The force placed on valve or leafe springs is probably an order of magnitude greater than that placed on any magazine spring. Valve springs are cycled at an astounding rate that would boggle the mind if anyone actually bothered to do the math. Leaf springs store and return more kenetic energy that any mag spring will ever be subjected to. I am not a physics major, but I do know how much a car/truck weighs and works. There is no way a mag spring is under more strees than a valve or leaf spring.
Stress equals force divided by cross sectional area so not necessarily.
To add to this discussion I will say this: I keep range/training/competition mags and separate carry/SD mags. The newest mags, after testing, become carry mags.
It is a misconception that leaving the mag fully loaded weakens the spring.
Says who?
F-Trooper05
11-06-12, 09:27
Says who?
Engineers. You can leave a car parked in a garage for 100 years, and the shock absorbers won't need to be replaced. A mag spring is no different.
FWIW, I'm an engineer... ;)
FWIW, I'm an engineer... ;)
As am I...
Magic_Salad0892
11-06-12, 15:07
If keeping the magazine loaded doesn't change magazine tension then how come when the Gen4 Glocks came out and were oversprung people suggested locking the slide back and letting it sit for a few days to weaken the spring?
Then reporting that it worked...
If keeping the magazine loaded doesn't change magazine tension then how come when the Gen4 Glocks came out and were oversprung people suggested locking the slide back and letting it sit for a few days to weaken the spring?
Then reporting that it worked...
Because if something is repeated over and over and over on the errornet it must be true.
So please explain this. Why would it be different for a pistol magazine as opposed to a rifle magazine? There are plenty of knowledgeable engineers and rocket scientists who have stated many times over that compressing and decompressing the spring (cycling) is what causes wear or weakening.
Why all of a sudden would that change? Also, the carbine action spring in an M4 is only under a partial load or compression. So someone explain why it loses its' properties? It's called compression and decompression.
Doc. Holiday
11-06-12, 15:47
I wouldn't worry about your mag loosing it's tension for reasons that everyone else has already stated. Mags are designed to be used and abused for long periods of time (obviously I'm talking about quality brands, not chinacom crap).
DreadPirateMoyer
11-06-12, 18:28
Google stress relaxation in metals.......
It is a corollary to creep. Creep is movement along grain boundaries due to constant load, stress relaxation is movement along grain boundaries caused by a displacement, resulting in progressively lower stress (the material relieves the strain by shifting along grain boundaries).
This is a stress and time based phenomena.
The stress on the magazine spring is created by compression. The rate of relaxation increases with increasing stress levels. Decreasing the compression decreases the maximum stress experienced, extending useful life.
Note that some designs are more susceptible than others based on design goals.
The physical manifestation of this is that a magazine spring left loaded for an extended period of time will be shorter than a new one.
That reduction in length is proportional to a reduction in force.
This is really, really easy to prove. Take a Glock magazine that has been fully loaded for 6 months or more, disassemble it and compare the spring to a new one. It may still function, but that loss of length represents a loss of design margin.
Right. A fully-loaded spring will indeed be shorter than one never loaded. That's the initial set that all magazine springs take. However, take a fully loaded Glock magazine after one day, and after 10 years, and they will be the exact same length so long as neither has been cycled. Time means nothing here, as the engineers creating these things stay within the elastic limits prescribed by the materials (remember that class?).
You're also right that the shorter spring will have a loss in force compared to a brand new spring, but engineers designing magazines design to the fully-loaded spring's level of force, so it's all perfectly fine.
TL;DR: I'm an engineer, you're an engineer, and you should know these things already. A fully-loaded spring can be left fully-loaded indefinitely and not lose any power compared to the first day it was fully-loaded.
TL;DR: I'm an engineer, you're an engineer, and you should know these things already. A fully-loaded spring can be left fully-loaded indefinitely and not lose any power compared to the first day it was fully-loaded.
Unless it's a Mossberg 5rd spring. :D
Right. A fully-loaded spring will indeed be shorter than one never loaded. That's the initial set that all magazine springs take. However, take a fully loaded Glock magazine after one day, and after 10 years, and they will be the exact same length so long as neither has been cycled. Time means nothing here, as the engineers creating these things stay within the elastic limits prescribed by the materials (remember that class?).
You're also right that the shorter spring will have a loss in force compared to a brand new spring, but engineers designing magazines design to the fully-loaded spring's level of force, so it's all perfectly fine.
TL;DR: I'm an engineer, you're an engineer, and you should know these things already. A fully-loaded spring can be left fully-loaded indefinitely and not lose any power compared to the first day it was fully-loaded.
This is just wrong.
The rate of stress relaxation is decreases with decreasing stress, but essentially never stops as it becomes asymptotic to zero. That is why people talk about an initial set, because he rate is higher when the stress is higher, as the individual grains shift to relieve the strain, the spring shortens, as the spring shortens there is less stress, and on we go.
Look it up.
The classic test is bending a thin specimen over a curved mandrel and clamping it in place. We used to run these tests all the time to determine stress relaxation curves at different temperatures for different alloys.
When Larry Vickers suggested locking the slide back on the Gen4's, he was telling people how to take advantage of this.
The OP asked how to extend the useful life. Downloading lowers the maximum stress and therefore slows the rate at which the magazine spring loses force.
PS. a magazine spring leads a very different life than a valve spring.
Michael2007
11-06-12, 19:38
Well I'm not an engineer but i did sleep at a holiday inn last night and my two year old springs are the same length as my 1 year old springs. All kept fully loaded and cycled less often than i would like.
Time to jump in (the election returns are too depressing).
I keep reading these endless threads on how long to compress a magazine spring hoping to learn something, and I just get more confused. The conventional wisdom offered on-line is that springs do not weaken over time if left fully compressed, that compression and decompression is what weakens them. While simply repeating what one hears over and over again does not make it true, I'll accept this statement as fact (although even the experts don't seem to be in agreement).
The problem I find is this...
While it may be true that leaving a magazine spring compresed but unused (as in loaded storage) is less stressful than using the magazine, I have to think that it's even better to leave the magazine empty and the spring uncompressed (again - this is for magazines kept in storage).
Many compare leaving a magazine loaded over time to leaving ones car left on the tires, rather than up on blocks. The car's shock springs do not get damaged by letting the car sit. However, a car is typically not fully loaded to maximum capacity when it sits. It's actually at its "rest" weight (no driver, no passengers, no bags of sand in the trunk, etc). More akin to an empty magazine, not a full magazine.
All of the above is directed at magazines kept in storage. Do what you all want - I'll leave mine empty.
Now we get to magazines kept in a state of readiness. By definition, these magazines must be loaded to capacity, or near capacity. How long can they stay like this without feeding issues?
If one accepts that it's "using" magazines that weakens the spring, then one should not use their "ready" mags in weekly practice or periodic training. Use dedicated training mags instead. Save your ready mags for emergency use.
The idea of "resting" springs also makes no sense. If compressing a spring causes any loss of strength, decompresing it will not return the spring to its former robust self. If I take a magazine that has been fully loaded but unused for one year, unload all rounds and place the now empty magazine in storage for another year, will the spring be "stronger" after a year of "rest" than it was the moment I emptied it after being loaded for the first year? I doubt it.
I am not a metalurgist, but I cannot believe that a spring will slowly get longer as it rests, gaining strength until it approached its "like new" condition. If leaving a spring compressed causes any loss of strength, "resting" the spring will merely stop the process, it won't reverse it.
As I see it - for maximum spring life, leave any storage magazines empty. Load them when and if you need them. Have dedicated training magazines. Have a few ready magazines (perhaps down loaded 1 or 2 rounds). After initial testing, leave them loaded, but unused. Perhaps replace the springs every few years (or decades).
Do I have this about right?
FWIW, I'm an engineer... ;)
Time to jump in (the election returns are too depressing).
I keep reading these endless threads on how long to compress a magazine spring hoping to learn something, and I just get more confused. The conventional wisdom offered on-line is that springs do not weaken over time if left fully compressed, that compression and decompression is what weakens them. While simply repeating what one hears over and over again does not make it true, I'll accept this statement as fact (although even the experts don't seem to be in agreement).
The problem I find is this...
While it may be true that leaving a magazine spring compresed but unused (as in loaded storage) is less stressful than using the magazine, I have to think that it's even better to leave the magazine empty and the spring uncompressed (again - this is for magazines kept in storage).
Many compare leaving a magazine loaded over time to leaving ones car left on the tires, rather than up on blocks. The car's shock springs do not get damaged by letting the car sit. However, a car is typically not fully loaded to maximum capacity when it sits. It's actually at its "rest" weight (no driver, no passengers, no bags of sand in the trunk, etc). More akin to an empty magazine, not a full magazine.
All of the above is directed at magazines kept in storage. Do what you all want - I'll leave mine empty.
Now we get to magazines kept in a state of readiness. By definition, these magazines must be loaded to capacity, or near capacity. How long can they stay like this without feeding issues?
If one accepts that it's "using" magazines that weakens the spring, then one should not use their "ready" mags in weekly practice or periodic training. Use dedicated training mags instead. Save your ready mags for emergency use.
The idea of "resting" springs also makes no sense. If compressing a spring causes any loss of strength, decompresing it will not return the spring to its former robust self. If I take a magazine that has been fully loaded but unused for one year, unload all rounds and place the now empty magazine in storage for another year, will the spring be "stronger" after a year of "rest" than it was the moment I emptied it after being loaded for the first year? I doubt it.
I am not a metalurgist, but I cannot believe that a spring will slowly get longer as it rests, gaining strength until it approached its "like new" condition. If leaving a spring compressed causes any loss of strength, "resting" the spring will merely stop the process, it won't reverse it.
As I see it - for maximum spring life, leave any storage magazines empty. Load them when and if you need them. Have dedicated training magazines. Have a few ready magazines (perhaps down loaded 1 or 2 rounds). After initial testing, leave them loaded, but unused. Perhaps replace the springs every few years (or decades).
Do I have this about right?
The science behind springs is not hocus pocus or true because people keep repeating it. It is a very much tested engineering science. The best advice I could give to really understand it is to pick up a solid mechanics textbook, turn to the chapters on springs and read it. Or better yet start studying mechanical engineering.
To really have a solid answer for the posed question in this thread one would need to specify the exact magazine body and spring. Then you could start answering at what loading will you damage the spring, and what those effects may be.
There are lots of springs that are under continuous loads for long periods of time that still perform as designed. Probably the worst thing that you could do is try to somehow "fix" a spring by stretching it or doing something similar.
Personally I've never had a magazine fail to operate because of continued loading. I've never really heard of anyone else having it happen either. And if I did hear about it, and it was from somebody that was in the military speaking about an issued magazine, I would probably discount it to some idiot who had the magazine before him "stretching" the spring while he was waiting for his buddy to pass him a cleaning rod section to scrape his crown.
DreadPirateMoyer
11-07-12, 03:08
I don't think I'm the one who needs to look things up.
Yes, stress relaxation happens in metals. No, it is not asymptotic about zero for steel. Almost no Hookean metals (steel is Hookean) are.
So long as a steel is kept at the same temperature within its elastic range, a constantly-applied force will cause the material to "bottom out" at some stress level (the asymptote you speak of) after a period of time. The material will never go below this stress level unless more stress/strain is added. Here are some charts to prove it:
1. Top chart is the relevant one here. Notice how the materials begin to bottom out far above zero. http://ars.els-cdn.com/content/image/1-s2.0-S0921509312010556-gr8.jpg
2. This is an oldschool paper studying one of the most widely-used tests for measuring stress relaxation in metals. Notice how neither metal hits an asymptote of zero? Steel is the same. http://www.springerlink.com/content/x6g8216272rrp245/fulltext.pdf
Now, as you can tell in the second link, the stress at which a material bottoms out depends, in the case of a magazine spring, on the material itself and the load applied to it. In our case, the material (steel) and load (the amount the spring is compressed by the rounds) are known, and the stress relaxation curve can be found. Using this curve, engineers know what stress level magazine springs bottom out at (and it's not zero) due to stress relaxation. Guess what level of force engineers then design the magazine to function under?
TA-DAAAA! The asymptote you spoke of. This is the initial set magazine springs originally take, which happens fairly quickly. Once the stress relaxation happens, that mag spring ain't losing any power until it's cyclically loaded.
Now, can we please end this debate once and for all? As a matter of scientific principle and fact, once a magazine spring takes its initial set (which happens within minutes of loading), keeping it fully loaded will not weaken it no matter how long it is kept fully loaded. End of story.
I've been thinking about how your tests were showing an asymptote of zero, and after rereading your reply, I'd be willing to bet you were taking the materials out of the elastic range and into the plastic range; not something that happens in magazines.
This is just wrong.
The rate of stress relaxation is decreases with decreasing stress, but essentially never stops as it becomes asymptotic to zero. That is why people talk about an initial set, because he rate is higher when the stress is higher, as the individual grains shift to relieve the strain, the spring shortens, as the spring shortens there is less stress, and on we go.
Look it up.
The classic test is bending a thin specimen over a curved mandrel and clamping it in place. We used to run these tests all the time to determine stress relaxation curves at different temperatures for different alloys.
When Larry Vickers suggested locking the slide back on the Gen4's, he was telling people how to take advantage of this.
The OP asked how to extend the useful life. Downloading lowers the maximum stress and therefore slows the rate at which the magazine spring loses force.
PS. a magazine spring leads a very different life than a valve spring.
As a matter of scientific fact (and anyone that has actually done it knows it), in handguns the initial set DOES NOT happen "within minutes of the first loading". Not in mag springs, not in recoil springs.
It is common in glocks, for example, for a 15 rd. mag to admit only 14 initially. You have to let it rest loaded for a couple of days and load and unload several times until you can load them to full capacity.
But you are right, for all practical purposes once the spring takes its initial set stays there until the cyclic loading wears it.
Mag springs are very tricky because they are not helicoidal, so they have areas with much higher stress than others.
And I wonder why I get confused!
Simple solution (the one I've lived by for several years) - leave magazines kept in storage empty. You won't have to worry about them taking a set. Have dedicated training magazines, use them until they break. Keep your ready magazines loaded. Download single column mags by one round, double column mags by two rounds (more for peace of mind, though there is some anecdotal data that this does help prolong spring life).
Move on.
DreadPirateMoyer
11-07-12, 08:04
As a matter of scientific fact (and anyone that has actually done it knows it), in handguns the initial set DOES NOT happen "within minutes of the first loading". Not in mag springs, not in recoil springs.
It is common in glocks, for example, for a 15 rd. mag to admit only 14 initially. You have to let it rest loaded for a couple of days and load and unload several times until you can load them to full capacity.
But you are right, for all practical purposes once the spring takes its initial set stays there until the cyclic loading wears it.
Mag springs are very tricky because they are not helicoidal, so they have areas with much higher stress than others.
It does take the initial set within minutes if you aren't a girl and can load your mag to capacity out of the box. :-P
And I've compared springs before. Within 15 minutes, my G17 springs were set.
DreadPirateMoyer
11-07-12, 08:09
And I wonder why I get confused!
Simple solution (the one I've lived by for several years) - leave magazines kept in storage empty. You won't have to worry about them taking a set. Have dedicated training magazines, use them until they break. Keep your ready magazines loaded. Download single column mags by one round, double column mags by two rounds (more for peace of mind, though there is some anecdotal data that this does help prolong spring life).
Move on.
Nothing bad about storing spare mags unloaded, but as we just discussed, there's absolutely no reason to do any of the rest of what you said. The anecdotal data is wrong. Your magazines will take a set so quickly after fully loading them that trying to avoid that by downloading them just lowers your chances of survival if you need that extra bullet or two.
Load your mags to full. They were designed that way. Move on.
(unless you can't load mags on a closed bolt ;))
I remember drinking beer in college with E majors of various types. The more beer that flowed, the more math, formulas, and dick measuring between E disciplines there was.
Eventually, they realized that we non-Es had left with their women hours earlier. :D
Skintop, that's funny (and was frequently true).
Dread Pirate - the anecdotal data I was referring to was from Chuck Taylor and his G17 torture test. I don't have the details in front of me, but if memory serves, he had feeding issues with his G17 mags after tens of thousands of rounds, fixed when he replaced the springs. After downloading these magazines by I think two rounds, the feeding issues went away (after firing many more tens of thousands of rounds).
I do agree that topping of your mags makes tactical sense, and while I agree that leaving mags fully loaded probably causes no longterm harm, I am skeptical enough that my storage mags shall remain empty while I vacillate on how to store my ready mags.
I don't think I'm the one who needs to look things up.
Yes, stress relaxation happens in metals. No, it is not asymptotic about zero for steel. Almost no Hookean metals (steel is Hookean) are.
So long as a steel is kept at the same temperature within its elastic range, a constantly-applied force will cause the material to "bottom out" at some stress level (the asymptote you speak of) after a period of time. The material will never go below this stress level unless more stress/strain is added. Here are some charts to prove it:
1. Top chart is the relevant one here. Notice how the materials begin to bottom out far above zero. http://ars.els-cdn.com/content/image/1-s2.0-S0921509312010556-gr8.jpg
2. This is an oldschool paper studying one of the most widely-used tests for measuring stress relaxation in metals. Notice how neither metal hits an asymptote of zero? Steel is the same. http://www.springerlink.com/content/x6g8216272rrp245/fulltext.pdf
Now, as you can tell in the second link, the stress at which a material bottoms out depends, in the case of a magazine spring, on the material itself and the load applied to it. In our case, the material (steel) and load (the amount the spring is compressed by the rounds) are known, and the stress relaxation curve can be found. Using this curve, engineers know what stress level magazine springs bottom out at (and it's not zero) due to stress relaxation. Guess what level of force engineers then design the magazine to function under?
TA-DAAAA! The asymptote you spoke of. This is the initial set magazine springs originally take, which happens fairly quickly. Once the stress relaxation happens, that mag spring ain't losing any power until it's cyclically loaded.
Now, can we please end this debate once and for all? As a matter of scientific principle and fact, once a magazine spring takes its initial set (which happens within minutes of loading), keeping it fully loaded will not weaken it no matter how long it is kept fully loaded. End of story.
I've been thinking about how your tests were showing an asymptote of zero, and after rereading your reply, I'd be willing to bet you were taking the materials out of the elastic range and into the plastic range; not something that happens in magazines.
I was trying to describe the shape of the curve, but my word choice was not sufficiently precise. You are correct that the final value is well above zero for elastic loading, however, the loss of initial stress is decreased by decreasing the maximum stress.
Limiting the maximum stress, i.e. downloading, decreases how much the spring loses its ability to apply force to the stack.
The time scales of the paper cited are particular to the alloys and temperatures tested.
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