How long can you keep magazine springs under tension?


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Hokkmike
June 5, 2006, 09:09 AM
I bought an additional magazine for my little .380 Bersa Thunder. I will keep one magazine loaded.

How long can I keep the magazine full and keep the spring under pressure until the spring develops a "memory" and loses its ability to force a round into the chamber?

Is there a strategy I can use, say - load one for a month, then empty it and load the other for a month, two months, three, etc., that would maximize the life of the magazine?

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doubleaes2
June 5, 2006, 09:20 AM
A quality spring only accumulates wear when it is compressed and extended. If you still feel uncomfortable keeping the mags loaded for an extended period of time, download by one round.

Walt Sherrill
June 5, 2006, 09:36 AM
According to the experts, folks like the engineers at Wolff springs, and a metallurgist or two who have participated here and elsewhere, it depends:

Springs wear, over time, through use. Working the springs (flexing them, as in normal use) will cause wear, over time. But they wear FASTER and more dramatically as they are pushed (expanded or compressed) to their design limits.

A well-designed, quality spring in a high-cap mag, left fully loaded and fully compressed will, generally, degrade faster than the same spring downloaded a round or two. But mag design and how the spring was made to work with the mag matters, too.

A 1911 7-round mag left fully compressed for decades probably won't show significant performance degradation. But an 8-round mag for the 1911 won't hold up as well.

I'm a CZ enthusiast, and know that the 10-round mags and the 15 or 16 round CZ mags use the same springs. Leaving a 10-rounder fully compressed is a lot easier on the springs than leaving a 16-rounder fully compressed. The shared springs in 10-round and 15+ round mags seems to be the case for many gun makers. The hi-cap mags work the springs harder than lower-cap mags.

Several members here are into airguns, many of which use springs as the source of propelling force. They know a lot about springs -- and they'll tell you that leaving a spring FULLY COMPRESSED can be the kiss of death to a spring's life. Less than fully compressed, it can be a different story.

I'd suggest that if you have high-caps, and must leave the gun loaded, download a round or two. Or simply plan on replacing the springs a little more often.

Lou629
June 5, 2006, 12:22 PM
I had similar concerns when i got my first auto-loader years ago. I've done the 'once-a-month' switch with the 2 mags. that came with it for going on 16 years now. The gun is a BHP and the mags. were new from factory, so i knew i was starting with quality products. i don't know if this would be a good idea to apply in all cases, especially if you were to get a few cheaper after-market brand of magazines .
Anyway, my magazines are well broken-in by now as far as ease of loading them is concerned, and they still continue to function flawlessly when i take the thing to the range.

PS- i never loaded the mags to full (13) capacity during this time, i usually kept the count somewhere between 10/11/12 depending on my mood-of-the-moment over the years. ymmv.

usp9
June 5, 2006, 01:22 PM
...and forget 'em. If you want to cycle through your mags, go shoot once a year, that'll do it. With modern mags this is simply not a worry.

nero45acp
June 5, 2006, 09:40 PM
Anyone have any idea how long a USGI M1 Carbine mag (bought several unissued ones a few years ago) will last if left loaded with 14rds, rather than a full 15? (The M1 Carbine is my HD/SHTF carbine.)


nero

Crosshair
June 5, 2006, 10:40 PM
I load my 30 round AK mags to 20 rounds (Cause Wolf comes 20 to a box.:rolleyes: ) and I have left them loaded for over a year with no problems. All you have to do is tap the mag to make sure that all the rounds are against the back of the mag before you put it in the rifle. (That's why in war movies they tap the mag against their helmet.) This prevents feeding malfunctions.

gazpacho
June 5, 2006, 11:16 PM
The only way to answer your specific question is to test an OEM Bersa mag. Buy another magazine and mark it in a way where the mark won't come off. Load it up fully and stash it. Only bring it out when you go to the range. Use the mag at the range as you would normally do. If you want, keep track of how many times you reload the mag. At the end of your range session reload the mag and stash it away again. Report your results whenever the question comes up again on this forum (about every three months or so).

I have 1911 mags that have been continuously loaded for almost five years now, and are showing no evidence of wearing out.

Cuda
June 6, 2006, 01:24 PM
I have range use mags and SD mags. The SD are always full and ready for use if needed. The range mags are unloaded unless being used. At this point I've not seen any degradation of the springs.


C

wrangler5
June 6, 2006, 03:20 PM
I've seen a report of a 1911 magazine that was stored fully loaded for 70+ years and functioned perfectly when tried.

This subject comes up fairly regularly, and in one thread (somewhere, don't know where) a metallurgist reported rather authoritatively that the "wear" on a magazine spring comes from cycling it full to empty and back again, not from compressing the spring and leaving it compressed. So you'll "wear out" a magazine faster if you cycle ammo through it than if you just load it up and leave it.

There was an exception to this general rule, and that is if the spring is compressed beyond some elastic limit (I think he called it). If you compress a spring TOO far it may not come back fully to its uncompressed length and strength, even if you onlly compress it once. The concern arises particularly in high capacity magazines where the last round puts a real scrunch on the spring (design problem) or where you try to squeeze one extra round in (operator error.)

The conclusion was, load 'em up and leave 'em. If you're concerned about potential damage, download by one round as others have suggested, but do not load and unload a mag thinking you're extending the life of the spring.

Newton
June 6, 2006, 11:46 PM
Since LEOs keep their magazines fully loaded for months on end, I doubt it's much of a problem.

The only people who seem to suffer from spring burn out in their magazines are the military guys who constantly compress and release springs due to the number of rounds they typically put through service weapons.

Fully loaded 1911 magazines have been found 60 years after they were loaded, and they still worked perfectly.

Walt Sherrill
June 7, 2006, 07:12 AM
Since LEOs keep their magazines fully loaded for months on end, I doubt it's much of a problem.

Not really. They typical LEO shoots his gun very little, and then primarily when he's qualifying, which may be as infrequently as once or twice a year.

LEO, with exceptions, are NOT gun USERS or SHOOTERS, but gun CARRIERS. A surprisingly small number of them are truly gun enthusiasts. They could have a mag problem and not know it until its time to use the gun. Then, too, they have armorers who look for things like springs that need replacement...

The only people who seem to suffer from spring burn out in their magazines are the military guys who constantly compress and release springs due to the number of rounds they typically put through service weapons.Compressing and releasing springs do cause long-term wear, but so does compressing them fully when loading them to the max.

Fully loaded 1911 magazines have been found 60 years after they were loaded, and they still worked perfectly.True. But, keep in mind that those are all seven rounders. The same is not true 8 rounders, which have long been the source of problems for 1911 shooters.

Ten-round mags in other guns will work well after long-term storage, but hi-caps can be a problem.

I download everything I have, when not carrying. In most cases, most of my mags are empty. A gun in a bedside safe it fully loaded, as is my carry gun. The rest are left empty after last use. The only springs I've ever had problems with are in my hi-cap mags -- and they tend to loosen up and cause premature lock-back (by allowing the top round to slide around). That's my sign to get new mag springs.

Hal8000
June 7, 2006, 12:12 PM
My Sig P226 is 14 years old and has had 15,000 rounds cycled through it using the same factory high cap mag that came with it... I keep the mag stored fully loaded. I have used the one mag for all of my shooting, only because I'm lazy and only want to clean one mag when I'm through shooting. (this is not my carry mag anymore)

While the spring is noticeably weaker, and easier to load, I've yet to have any kind of failure from this mag... (or pistol!)

It's my opine that a stronger spring will over come a dirtier mag. I think if the mag is kept clean, then a weaker spring will continue to function...
Dirt will cause an older/weaker springed mag to fail quicker than a newer/stronger springed mag...

Ala Dan
June 7, 2006, 12:19 PM
As a former LEO, I use to inspect and rotate my magazines every 30
days; mainly as a precaution.:uhoh: I know, that action probably was
not necessary; but it definitely made me feel better as here down
south the humidity can rake havoc on men, and there equipment.

Of course, I'm an exception too the rule; as I shoot a lot more ammo
than most officers, so I NEVER had a problem with stale ammo~!:D

saltydog452
June 7, 2006, 12:51 PM
Rotate the mags AND the ammunition.
Whether they 'need it' or not...you'll never know for sure.
Key it in to other routine maintence obligations such as oil change.
Or quartely statements..whatever works for you.
Do it at the range.

Several good reasons for doing so.
You know what they are.
This would also be a good time to change out the batteries in your flashlight(s).
And batteries for the smoke detectors.

Consider it another timely 'routine maintence' obligation.

salty.

Magnumite
June 7, 2006, 04:00 PM
AAbout the carbine mags. I inherited one in '92, along with mags and ammo. Most the mags were already loaded, from the military, with the rubber protective tops on them. 1960's headstamps on the ammo. No problems of any type were experienced.

tegemu
June 7, 2006, 04:49 PM
Indefinately.

CZguy
June 7, 2006, 06:35 PM
I've seen a report of a 1911 magazine that was stored fully loaded for 70+ years and functioned perfectly when tried.

This subject comes up fairly regularly, and in one thread (somewhere, don't know where) a metallurgist reported rather authoritatively that the "wear" on a magazine spring comes from cycling it full to empty and back again, not from compressing the spring and leaving it compressed. So you'll "wear out" a magazine faster if you cycle ammo through it than if you just load it up and leave it.

There was an exception to this general rule, and that is if the spring is compressed beyond some elastic limit (I think he called it). If you compress a spring TOO far it may not come back fully to its uncompressed length and strength, even if you onlly compress it once. The concern arises particularly in high capacity magazines where the last round puts a real scrunch on the spring (design problem) or where you try to squeeze one extra round in (operator error.)

The conclusion was, load 'em up and leave 'em. If you're concerned about potential damage, download by one round as others have suggested, but do not load and unload a mag thinking you're extending the life of the spring.

This is a really good post. You have taken all of the emotion out of it and are just dealing with the facts of physics. The info on Wolff springs site backs this up also.
I wish "myth busters" would do a segment on this, and put it to rest once and for all.

Now, on to something that's never been covered like, can a bronze cleaning brush wear out a .22 LR barrel.
(I wouldn't dare mention this over at rimfire.com

Walt Sherrill
June 7, 2006, 07:00 PM
Realize, too, that rotating mags doesn't do a thing to increase spring life. Mags don't heal or refresh themselves when they're unloaded and left unused.

All ROTATING mags does is spread the "wear" over several mags, rather than putting it all on one mag -- delaying the time when the springs must be replaced -- but increasing the number of springs that must be replaced when that time finally arrives.

Nothing wrong with rotating them, but its not really doing anything. Sort of like rotating shoes...

Mannlicher
June 7, 2006, 10:59 PM
after a mag was kept loaded for say 50 years, I might be concerned.

brainwealth
February 14, 2015, 01:14 PM
1. What is the difference between conventional and variable recoil springs?
The difference is both physical and operational. With a conventional spring, all the coils are spaced equally apart, except for the closed ends. In a variable recoil spring the space varies between coils with less space between coils at one end and more space between coils at the other end.

The way the two springs store energy is also different. For example if a conventional recoil spring is compressed 1/2", it might store 1 pound of energy. For every additional 1/2" this spring is compressed it would then store 1 additional pound of energy. When a variable recoil spring is compressed 1/2", it might store 1/4 pound of energy. The next half inch of compression might store 1/2 pound, the next half inch might store 3/4 pound and so on. In other words, a conventional spring stores energy on a straight line and a variable spring stores energy on a curve. If both springs are rated at 16 pounds, they will both store 16 pounds when compressed to the same working length, but the way they get to 16 pounds is different.

2. Should I use a conventional or variable spring when both are available?
The choice is often very subjective. Conventional recoil springs are particularly beneficial when shooting heavier loads where keeping the slide closed as long as possible is desired. Variable recoil springs reduce the battery load values with increasingly greater recoil load values. This results in easier unlocking, improved recoil energy storage, dampening, feeding, breaching and lockup. Variable recoil springs are particularly beneficial with compensated pistols and when using light target loads where less recoil energy is available. The "correct type" of recoil spring is best determined through experimentation and your own personal preference.


3. What weight recoil spring should I use with a particular load?
This is a very common but hard question to answer in exact terms and in most cases an exact answer is not possible. There are many factors which influence the correct weight recoil spring to use. These factors include the particular ammunition brand and load, individual pistol characteristics, individual shooting styles and your individual, subjective feeling of how the gun shoots and should feel.

The factory spring weight is designed to operate the pistol with what would be considered average loads, plus or minus a little. It is not uncommon for manufacturers to specify what they consider a factory ammunition load.
In general terms, the heaviest recoil spring that will allow the pistol to function reliably is the best choice - tempered by the above factors. As a rule of thumb, if your spent casings are first hitting the ground in the 3 to 6 foot range, then the recoil spring is approximately correct. If you are ejecting beyond the 6-8 foot range, then a heavier recoil spring is generally required. If your casings are ejecting less than 3 feet, a lighter recoil spring may be needed to assure reliable functioning.

Taking these factors into consideration, it then comes down to how the gun feels and performs when shooting - in your judgment. However, using too light a recoil spring can result in damage to the pistol and possible injury to you.

4. How often should I change my springs?
The performance of your gun is the best indicator of when a spring needs to be replaced. Factors such as increased ejection distance, improper ejection and/or breeching, lighter hammer indents on primers, misfires, poor cartridge feeding from magazines, frequent jams, stove pipes and other malfunctions are all possible indications of fatigued springs or improper springs.

Springs such as magazine springs, striker springs and recoil springs are subjected to higher stress levels and will require more frequent replacement than other lower stressed springs such as firing pin springs and hammer springs.

Wolff springs are made with the highest grade materials and workmanship. Most Wolff [recoil] springs will remain stable for many thousands of rounds. Some recoil springs in compact pistols, especially where dual springs are used or are replaced by a single spring may require changing after 500 - 1500 rounds. Springs that become rusty, bent or otherwise damaged should always be replaced. Again, changes you observe in your firearm's performance are the best indicators that a change is needed.

5. How often should I change magazine spring? Should I unload my magazines, rotate magazines, load with fewer than the maximum rounds?
Magazine springs in semi-auto pistols are one of the most critical springs and are the subject of much debate and concern. Magazines which are kept fully loaded for long periods of time, such as in law enforcement and personal/home defense applications, will generally be subject to more fatigue than the weekend shooter's magazine springs in which the magazines are loaded up only when shooting.

Magazine design and capacity also affect the longevity of the spring. In many older pistol designs, maximum capacity was not the always the goal such as with the 7 round 1911 Colt magazines will last for years fully loaded. There was room for more spring material in these guns which reduces overall stress and increases the usable life of the spring.

More recently higher capacity magazine have become popular. These are designed to hold more rounds with less spring material often in the same space. This puts more stress on the spring and will cause it to fatigue at a faster rate. Unloading these magazines a round or two will help the life of the spring. Rotating fully loaded magazines will also help the problem somewhat but it is not always practical.

In applications where the magazine must be kept loaded at all times, a high quality magazine spring such as Wolff extra power magazine springs, will provide maximum life. Regular replacement of magazine springs will provide the best defense against failure from weak magazine springs. Regular shooting of the pistol is the best way to be sure the springs are still functioning reliably.

6. My spring got shorter after I used it for a short time. Is it bad?
Most new springs will take a set when they are first compressed. That means they will shorten up. This is a normal event and you should not be immediately alarmed. The greater the stress on the spring, generally the more set that will occur. All Wolff springs take this set into consideration. The ratings of the springs you receive are the ratings after the set has occurred. After set has taken place, the spring should remain essentially stable for the life of the spring.

7. My lighter [recoil] spring is longer than the heavier spring for the same gun. Is this a problem?
Wolff offers many springs in different weights for the same use. Factors such as the size of the wire, the number of coils, the outside diameter of the spring as well as the free length determine the strength of a particular spring. Often, lighter springs are longer than heavier springs because lighter wires and/or a different number of coils are used. Free length is then adjusted to achieve the exact strength desired.

8. The spring I purchased is longer than the original spring so I don't think it will fit.
The free length of a spring is not the most important factor in determining whether it will fit. Many Wolff springs are longer than factory springs. This is normal and the spring will fit.

The more important factor in determining whether a spring will fit is the number of coils in the spring times the diameter of the wire. For example, take 2 springs - one is 7 inches long and the other is 4 inches long. If both springs contain the same number of coils and use the same size wire, both springs will compress to the same solid lengths. The strengths will however be quite different but both springs will fit in the same application.


9. What is the difference between a firing pin spring and a striker spring?
A firing pin spring is actually a return spring as it returns and keeps the firing pin retracted. The firing pin spring works in front of the firing pin pushing the firing pin away from the primer usually keeping it retracted in the slide. When the firing pin is struck by the hammer the impact force of the hammer overcomes the retraction force of firing pin spring and drives the firing pin into the primer.
A striker spring is actually the spring that causes the firing pin to striker the primer. The striker spring works behind the firing pin. When the gun is in the cocked position, the striker spring is compressed behind the firing pin. When the trigger is pulled the firing pin is released and the striker spring pushes the firing pin into the primer. While technically incorrect, a striker spring is often referred to as a firing pin spring.

moxie
February 14, 2015, 06:06 PM
Never had a problem. I keep mags for both pistols and rifles loaded to the max. Never download. They always feed properly. To be sure, test fire each one occasionally. If there's a problem, throw it out. Otherwise good to go. I've never had to toss one, but I check most anyway. Some mags I've overlooked have been loaded for more than 5 years and they worked just fine. Also make sure to clean the mag after firing, especially under the feed lips and around the follower. Crud is a far greater threat than spring compression.

GLOOB
February 14, 2015, 08:30 PM
How long? I dont' know but I'm trying to find out. I've kept all my handgun mags full for at least 4 years. Once they stop working, I will know when to change them in the future. :)

Schwing
February 14, 2015, 08:43 PM
This was a question I had about 20 years ago. At the time, my only handgun was a 92fs so I loaded one magazine up fully and left it that way. I take that magazine out 3 or 4 times a year and run a few loads of ammo through it and then store it full again.

Here we are 20 years later. It has yet to have a failure. I suspect I won't see one in my lifetime (at least that is caused by the magazine.)

Drail
February 15, 2015, 12:10 AM
I am always amazed at the number of people who are willing to actually believe that magazine springs never weaken, wear out or fail to feed reliably - only because they have never seen one do it. They wear out. You need to replace them before that happens or your pistol will stop running. Pay attention to how well the last round feeds. Once you see that - the spring is shot. The magazine spring is the most important spring in the gun IMO. If you work on guns for a few years you will find that 90% of reliability problems in most semi auto guns is - a weak magazine spring. Ask any good smith. I have seen plenty of guns that wouldn't run and suddenly ran perfectly with a new extra power magazine spring installed. The gun manufacturers think about "how many rounds can we cram in here?" and "how cheap can we buy these springs" in order to compete with the market today (which seems to be "capacity trumps everything else"). The end user should be much more concerned with feed reliability and place max capacity lower on their list of priorities. Section 5 of the Wolff printout pretty much says it all. I used to have to keep 6 pistols running under heavy use for a pistol team and guns used in NRA classes. We went through a lot of magazine springs. Wolff or ISMI are the best I have found and have kept all of my race guns running perfectly for many summers of match use. But eventually even they will wear out. Keep spares on hand.

Jlr2267
February 15, 2015, 12:20 AM
As long as you want to. Loading/unloading is what fatigues them.

Drail
February 15, 2015, 12:40 AM
Oversimplification. Loading and unloading is only one factor.

Jlr2267
February 15, 2015, 12:41 AM
Oversimplification. Loading and unloading is only one factor.
Please list others

AustinTX
February 15, 2015, 01:38 AM
As long as you want to. Loading/unloading is what fatigues them.

The idea that this is the only factor is a myth. A very stubborn one, but a myth all the same.

Read the Wolff FAQ. Then read this: http://thefiringline.com/forums/showthread.php?t=557865

Jlr2267
February 15, 2015, 02:32 AM
The idea that this is the only factor is a myth. A very stubborn one, but a myth all the same.

Read the Wolff FAQ. Then read this: http://thefiringline.com/forums/showthread.php?t=557865

There is no mechanism whereby a spring can experience fatigue, other than load/unload cycles (be they mechanical or thermal). This is a simple fact, and is inherent in the very *definition* of fatigue. If there are other mechanisms for metal fatigue, I'd like to know what they are, because all the jet engine and gas turbine hardware I've designed over the last 2 decades will need a redesign.

The Wolff FAQ does not suggest otherwise, nor does the spring experiment linked.

If you are suggesting that springs can take a permanent set, giving a shorter uncompressed length after being loaded, this is true, but has literally nothing to do with the length of time under load. It has everything to do with the amplitude of those initial loads which, when combined with residual stresses in the steel, can cause localized plastic deformation, resulting in a shorter spring. This "set" occurs within a few initial loads, and the spring will remain at that "set" length indefinitely, unless loaded beyond the material's yield strength, or heated to 600F+ degrees while compressed.

The only time dependent mechanism for plastic deformation in metals is creep. Magazine springs in normal service use are nowhere near the temperature needed to see measurable creep in spring steel.

JohnKSa
February 15, 2015, 02:58 AM
This "set" occurs within a few initial loads...So what you're claiming is that 4-6 loading cycles of the P95 magazine, accomplished over a 5 minute interval, would have resulted in exactly the same spring strength decrease that occurred over 160 days (involving 4-6 loading cycles) in the test.

I guess I could test that. Start with some identical new mags, and put them all through exactly the same loading/unloading cycles but leave some loaded and some unloaded.

In fact, I could probably make a stab at it in a relatively short time. I think I have a couple of new P95 mags. I could load/unload them multiple times over a short time period and see what effect it has on the strength....unless loaded beyond the material's yield strength...I assume that you are saying unequivocally that no magazine, when fully loaded, loads the spring beyond the material's yield strength.

Jlr2267
February 15, 2015, 03:13 AM
So what you're claiming is that 4-6 loading cycles of the P95 magazine, accomplished over a 5 minute interval, would have resulted in exactly the same spring strength decrease that occurred over 160 days (involving 4-6 loading cycles) in the test.

I am saying that the time at full load has no impact whatsoever, only the amplitude and number of loads


I guess I could test that. Start with some identical new mags, and put them all through exactly the same loading/unloading cycles but leave some loaded and some unloaded.I assume that you are saying unequivocally that no magazine, when fully loaded, loads the spring beyond the material's yield strength.

If it was designed that way, it'd a very bad design.

If you took 100 springs, cycled 50 of them immediately, took the other 50 and cycled them the same number of times as the 1st group, and to the same max/min loads, but held each cycle on the compression side for 6 months, the 2 groups would be indistinguishable in terms of overall length (assuming room temperature)

JohnKSa
February 15, 2015, 03:29 AM
I am saying that the time at full load has no impact whatsoever, only the amplitude and number of loadsThis doesn't explain why spring-piston airgun manufacturers have always indicated that shooting the guns (cycling the springs) isn't a big deal but that leaving them cocked for long periods (compressing the spring for long periods) is bad for the gun. They apparently know what they're talking about as there have been at least two independent testers that have shown that leaving spring-piston airguns cocked for long periods does, indeed, reduce spring strength while shooting them without leaving them cocked for long periods does not.If you took 100 springs, cycled 50 of them immediately, took the other 50 and cycled them the same number of times as the 1st group, and to the same max/min loads, but held each cycle on the compression side for 6 months, the 2 groups would be indistinguishable in terms of overall length (assuming room temperature)Ok, sounds like a fun test.

I'll post the results after I've collected enough data to make a clear call one way or the other. I've got 4 identical new P95 mags and I'll run the test on them.

Steve C
February 15, 2015, 05:18 AM
My experience has been that springs give you plenty of warning that they are getting weak well before they fail. First you will get failure to hold open the slide after the last shot which makes sense as this is when they are at full extension and have their weakest pressure. When this symptom appears the magazine still works feeding rounds so there is no "danger" of having an inoperable handgun. Simply replace the spring and you are good to go.

I've had double stack magazine springs (Glock) need replacement after a dozen years of use. Have never needed replacement of a spring in a single stack magazine or rifle mag.

ku4hx
February 15, 2015, 05:49 AM
I bought my first center fire semi auto in 1969; a Browning Hi-Power. I still have the original magazine and it still has the original spring. One data point does not make a research study, but that magazine still works just fine and I'd guess it's been loaded maybe 25% of the time between then and now.

I've got Ruger standard .22 Long Rifle magazines that date back to 1964, S&W 1006 and Glock 20 magazines I bought in 1991 ... and so forth and so on.

Load 'em and shoot 'em until they stop working and then buy replacement springs; I prefer Wolff's. But the thing is, I've got a box full of spare magazine springs I've bought over the years and the only ones I've ever used were to replace factory springs that were underpowered. That was our Ruger KP90s and it's been years since I replaced them; no problems since.

GBExpat
February 15, 2015, 06:58 AM
How long can you keep magazine springs under tension?At least 9 years ... just like this ancient Thread.

HKGuns
February 15, 2015, 08:43 AM
Someone's off to a great start. First post, record length and dredges up a thread from 2006 when spring technology just might have been different.

j357
February 15, 2015, 10:30 AM
+1^ and their post is basically a drive by paste from the Wolff website, which was mentioned in post 18.

Walt Sherrill
February 15, 2015, 10:34 AM
Someone's off to a great start. First post, record length and dredges up a thread from 2006 when spring technology just might have been different.

Not everybody has been participating here the whole time, and not everybody agrees on the topic.

That said, as best I can tell, spring technology hasn't changed much at all in the last 8-9 years. What HAS changed is that more and more guns are being made smaller, or with greater round capacity -- and in THOSE guns, the springs are asked to do more than was the case in the past and often asked to do it in less space and with less spring material. Magazine springs and recoil springs in some of these guns have become "sacrificial" parts.

The recoil spring of a Rohrbaugh R9, a very small 9mm semi-auto, for example, has a recommended service life of 250 cycles-- although I'm sure it'll last longer. The recoil springs for some of the small/compact 1911s also have a much shorter recommended life than their full-size models. And springs in ultra-high-cap mags or mags for very small pistols holding 8-10 rounds will likely have shorter services lives than other mags, especially if those mags are left fully loaded.

For many (perhaps most) guns, it's not likely to be an issue, but for some of the smallest guns or guns using mags with very large capacities, it can (not WILL) lead to shorter spring life.

Jlr2267
February 15, 2015, 10:39 AM
This doesn't explain why spring-piston airgun manufacturers have always indicated that shooting the guns (cycling the springs) isn't a big deal but that leaving them cocked for long periods (compressing the spring for long periods) is bad for the gun. They apparently know what they're talking about as there have been at least two independent testers that have shown that leaving spring-piston airguns cocked for long periods does, indeed, reduce spring strength while shooting them without leaving them cocked for long periods does not.Ok, sounds like a fun test.

I'll post the results after I've collected enough data to make a clear call one way or the other. I've got 4 identical new P95 mags and I'll run the test on them.

Maybe toy gun manufacturers have discovered some mechanical failure mode that's escaped detection by the aerospace and power generation industries for decades...but I seriously doubt it.

Do you know how many mechanical "springs" are in a gas turbine or jet engine? I would think this mysterious phenomenon might have reared its ugly head by now in these industries, causing a catastrophic failure, if it were real.

I have spent, literally, tens of millions of dollars of my company's money characterizing mechanical properties of various alloys, primarily in fatigue and creep, and their interaction, and I can tell you with certainty that there is no time dependent deformation mechanism in metals in the temperature range where magazine springs operate. There is also no time dependence found in fatigue life, when the "hold time" is at temperatures below the creep regime...only the cycle amplitude and cycle count are important.

Walt Sherrill
February 15, 2015, 10:45 AM
...There is also no time dependence found in fatigue life, when the "hold time" is at temperatures below the creep regime...only the cycle amplitude and cycle count are important.

When you say "only the cycle amplitude and cycle count are important" " do you mean (with the underlined term) HOW FAR the metal is bent, compressed or stretched from it's starting/resting position? Or does that term mean something else?

Do you know how many mechanical "springs" are in a gas turbine or jet engine? I would think this mysterious phenomenon might have reared its ugly head by now in these industries, causing a catastrophic failure, if it were real.

It would interesting to learn of a few examples ... especially if their function is similar to that of a recoil spring closing a slide or magazine spring lifting a column of ammo to feed the next round.


.

Jlr2267
February 15, 2015, 10:54 AM
When you say "only the cycle amplitude and cycle count are important" " do you mean (with the underlined term) HOW FAR the metal is bent, compressed or stretched from it's starting/resting position?
Yes, how far (underlined part) and how many times.

GBExpat
February 15, 2015, 11:22 AM
Someone's off to a great start. First post, record length and dredges up a thread from 2006 ... ... and the record length first post wasn't even of his/her own creation but, rather, a Copy & Paste of text from the Wolff FAQ webpage.

Ayup, a great start for a new member. <chuckle>

Lycidas Janwor
February 15, 2015, 12:03 PM
if you have a 15 round magazine and you load it to 15, and then chamber a round, the magazine now only has 14 rounds in it, right? So this is the best way to keep a loaded gun and keep the magazine in top shape, correct?

Jlr2267
February 15, 2015, 12:11 PM
if you have a 15 round magazine and you load it to 15, and then chamber a round, the magazine now only has 14 rounds in it, right? So this is the best way to keep a loaded gun and keep the magazine in top shape, correct?
For a properly designed spring, it makes no difference.

Walt Sherrill
February 15, 2015, 12:13 PM
Yes, how far, and how many times.

What IF a gun designer chooses to use the same springs in a 10, 15, 16, 17, and 18 round mag (as has been the case with some CZs with which I have some familiarity)?

1) Should we expect to see the same life expectancy for all of those springs (i.e., for a given number of rounds fired)? Are we addressing the how many times issue?

2) Should we expect to see the same life expectancy for those springs based on the number of compression cycles? And does the DEPTH of the compression matter -- i.e., how far?

3) Or, is there another set of variables at play, such as a subtle combination of compressions and work done? Are some spring designed (as with the Rohrbaugh R9) to be sacrificial, because the desired performance isn't possible otherwise?

I would note that the 10-round application discussed here never pushes the mag spring anywhere near full compression, while the 18-round version, fully loaded, has the coils virtually stacked.

The amount of work done by the springs to fire the same number of rounds in mags that use the SAME SPRINGS is certainly different, too. The hi-cap mags will have cycled almost half as often but have done much more work with each full cycle lifting more rounds (and weight) with each of those cycles than the springs in the standard mags for the same number of rounds fired. Does that extra "work" have a measruable effect on spring life?

How about if the mags are left fully loaded for long periods? I would argue that the fully loaded mags have springs that are still working -- trying to press the column of ammo against the feed lips of the mag. If the mags are fully loaded and left setting on their base, they're trying to LIFT that weight. Does that WORK have any effect on spring life -- and does it's effect depend on HOW MUCH weight is involved in that work effort? If the weight of the rounds matter, storing mags upside down -- I've not seen that done -- might be a good thing to do... If the weight of the rounds matter, does it matter when cycling, too?

Re: air gun spring ...

What if the guys who make top quality air guns -- which are not TOYS (but a different type of weapon -- know that leaving the air gun's spring fully compressed leads to degradation, but leaving them uncompressed when not in use does not? I think that's the point that JohnKSa was addressing. Maybe there's no other way to get the desired performance out of a spring that can fit in the available space and offer appropriate spring life...

.

Jlr2267
February 15, 2015, 01:04 PM
What IF a gun designer chooses to use the same springs in a 10, 15, 16, 17, and 18 round mag (as has been the case with some CZs with which I have some familiarity)?

1) Should we expect to see the same life expectancy for all of those springs (i.e., for a given number of rounds fired)? Are we addressing the how many times issue?

I would expect a different spring life in each case because both the amplitude and cycle counts would vary


2) Should we expect to see the same life expectancy for those springs based on the number of compression cycles? And does the DEPTH of the compression matter -- i.e., how far?

both matter...cycles and "how far"


3) Or, is there another set of variables at play, such as a subtle combination of compressions and work done? Are some spring designed (as with the Rohrbaugh R9) to be sacrificial, because the desired performance isn't possible otherwise?

Work and compression distance in a spring (within the elastic range anyways) are uniquely related...there is no subtle combination because we know the relationship between the two, and they are just 2 ways of expressing the same thing (distance compressed)


I would note that the 10-round application discussed here never pushes the mag spring anywhere near full compression, while the 18-round version, fully loaded, has the coils virtually stacked.

The amount of work done by the springs to fire the same number of rounds in mags that use the SAME SPRINGS is certainly different, too. The hi-cap mags will have cycled almost half as often but have done much more work with each full cycle lifting more rounds (and weight) with each of those cycles than the springs in the standard mags for the same number of rounds fired. Does that extra "work" have a measruable effect on spring life?

Again, the "work" idea is just another way of saying "compression distance." The energy in a spring (and therefore the amount of work it can do) is directly related to how far it's compressed. If compressed, it *can* do work...when it's sitting there not decompressing, it's not doing any work...it's just sitting there.


How about if the mags are left fully loaded for long periods? I would argue that the fully loaded mags have springs that are still working -- trying to press the column of ammo against the feed lips of the mag.


you can argue with physics, but you'll lose that argument every time. No movement = no work


If the mags are fully loaded and left setting on their base, they're trying to LIFT that weight. Does that WORK have any effect on spring life -- and does it's effect depend on HOW MUCH weight is involved in that work effort?

That's not work. When the spring lifts a round to the top of the magazine, that's work.


If the weight of the rounds matter, storing mags upside down -- I've not seen that done -- might be a good thing to do... If the weight of the rounds matter, does it matter when cycling, too?

The weight of the rounds does not matter. Only how far the spring is compressed.


Re: air gun spring ...

What if the guys who make top quality air guns -- which are not TOYS (but a different type of weapon -- know that leaving the air gun's spring fully compressed leads to degradation, but leaving them uncompressed when not in use does not? I think that's the point that JohnKSa was addressing. Maybe there's no other way to get the desired performance out of a spring that can fit in the available space and offer appropriate spring life...

.

I don't know much about airsoft or air gun springs, but I do know that the R&D and engineering which goes into developing them is miniscule when compared to more serious hardware, like jet engines and large rotating turbomachinery, where failures cost people their lives. I've been involved with designing the latter for a very long time, and spent many years getting graduate degrees in Engineering to prepare myself for that experience.

I'm more than willing to listen to a good explanation of this phenomenon, one that describes the physics, but so far I've not heard it, either here, while at university, or in my years in the industry.

Walt Sherrill
February 15, 2015, 03:37 PM
If the mags are fully loaded and left setting on their base, they're trying to LIFT that weight. Does that WORK have any effect on spring life -- and does it's effect depend on HOW MUCH weight is involved in that work effort? That's not work. When the spring lifts a round to the top of the magazine, that's work.

You seem to be saying that the physical size of the CARTRIDGE* is the key factor in spring compression, as it dictates the amount of spring compression (unless each bullets weighs a ton!!). If that is true -- and I'll accept your point that it is -- that means a column of fake wooden cartridges will have the same effect on a mag spring life as a column of heavier LEAD cartridges if both are stored for long periods, or when they're stripped from the mag. (This assumes that neither really overstressed the spring.) If that's the KEY factor, then I've learned something from this discussion, and you have my thanks. But that brings us back to another unresolved point...

If the AMOUNT of compression is a key factor [I'm not trying to disregard frequency of cycling], and we're using the same springs (as was the case with the CZ mags I cited), it would seem that springs that aren't FULLY COMPRESSED when used in fully loaded mags, will live longer lives than ones that are (or are near fully compression). A standard size CZ mag that holds 10 rounds is the same size as a standard size CZ mag that hold 16 rounds, and they use the same springs. I would expect the 10-round mags to outlive the 16 round mags, for the same number of rounds fired, even though the 10-round mags will have cycled more times. And over the years, that has been my experience with CZ mags.

Some of the others participating in earlier versions of this discussion -- several of whom were engineers, and one a metallurgist) made the point that nearly all materials pushed to their structural/elastic limits begin to degrade as they near those limits; the closer they get to that limit the more quickly the degradation occurs. Wikipedia says that this phenomenon is true of nearly all materials -- rubber, wood, steel, aluminum, glass, polymer, etc. As the discussion progressed, these same guys said that long periods of full (or near full) spring compression will degrade mag springs more quickly than leaving them less compressed. And in most cases, they'll degrade more rapidly than from a high number of cycles that didn't overdo compression.

I'll repeat a point for others reading here (I'm sure you understand): FULLY COMPRESSED and FULLY LOADED are not interchangeable terms. Many here seem to assume they are.

Wolff Springs advises downloading hi-cap mags a round or two to extend spring life. Do you disagree? It's arguably not necessary for ALL hi-cap mags, but perhaps for many. If you think that's bad advice, please tell us why? (It sure doesn't sell more mag springs...)

If you don't disagree with the Wolff advice, what's really different about the Wolff guideline and JohnKSa's point about air gun springs that degrade when left fully cocked, but live longer when left uncocked? Perhaps that particular spring design offers the best performance for the space and materials available when used in that manner...

I've come to think that some of today's smaller guns or higher cap mag designs push springs farther than they are ready to be pushed, and that a few of these designs have made their springs sacrificial components -- or put another way, "renewable resources." Do you disagree?

*first time through that said "bullet" which was not what I meant...

JohnKSa
February 15, 2015, 04:29 PM
Maybe toy gun manufacturers...The two tests I've seen were run on high-end airguns, many of them with custom springs installed and most of them costing as much or more than the average firearm.Do you know how many mechanical "springs" are in a gas turbine or jet engine? I would think this mysterious phenomenon might have reared its ugly head by now in these industries, causing a catastrophic failure, if it were real.I suspect that there might be a slight difference in design philosophy between someone designing a jet engine with springs in it and someone designing a magazine with a spring in it that can be purchased for about $10 and is easily replaced by an unskilled person in about 1 minute.

Anyway, debate is useless on this topic because everybody's an expert.

I'll run the test and we'll see what the results say.

4 brand new P95 mags--never been loaded.

1 will be left fully loaded. Only unloaded to test the springs at roughly monthly intervals.
1 will be left loaded 2 rounds under max. Only unloaded to test the springs at roughly monthly intervals.
1 will be be left unloaded and will be cycled (loaded fully and immediately unloaded) exactly the same number of times as the two being left loaded.
1 will be left unloaded and will be cycled (fully loaded and then immediately emptied) at least 2x more times than the rest of the mags in the test.

I won't get started for awhile. My current spring tester is tedious to use and I'm working on a new one that will be a lot faster and easier to use. The test will start when I finish it.

Jlr2267
February 15, 2015, 06:46 PM
If the AMOUNT of compression is a key factor [I'm not trying to disregard frequency of cycling], and we're using the same springs (as was the case with the CZ mags I cited), it would seem that springs that aren't FULLY COMPRESSED when used in fully loaded mags, will live longer lives than ones that are (or are near fully compression). A standard size CZ mag that holds 10 rounds is the same size as a standard size CZ mag that hold 16 rounds, and they use the same springs. I would expect the 10-round mags to outlive the 16 round mags, for the same number of rounds fired, even though the 10-round mags will have cycled more times. And over the years, that has been my experience with CZ mags.

I don't necessarily disagree with anything you've said here. Fatigue can be very much dependent on the loading history. A single, extreme load can do serious damage, and subsequent, smaller loads can rapidly deteriorate the part. On the other hand, loads below a certain threshold do no damage at all (in a practical sense) and the part lasts forever. The key point is that, at a given stress load (max/min) the spring has a finite number of cycles to failure...sprinkling in higher loads eats up a larger fraction of that life...but these 2 things (how much load, and how many times you load it) are the 2 factors controlling the life of the spring. How long you may hold it compressed does not matter, even if you are beyond the yield strength.

Wolff Springs advises downloading hi-cap mags a round or two to extend spring life. Do you disagree? It's arguably not necessary for ALL hi-cap mags, but perhaps for many. If you think that's bad advice, please tell us why? (It sure doesn't sell more mag springs...)

I don't think it's necessary to download, and if does anything at all, it would possibly shorten the life. If I've already fully loaded the magazine, downloading 2 rounds does not reduce any damage because there is no further damage occurring when the spring is sitting there loaded. By downloading it, you are actually adding to the fatigue damage (albeit an infinitesimally small amount, most likely).

I've come to think that some of today's smaller guns or higher cap mag designs push springs farther than they are ready to be pushed, and that a few of these designs have made their springs sacrificial components -- or put another way, "renewable resources." Do you disagree?

I would agree. There is a trade-off between a magazine spring that produces enough force to reliably feed a stack of ammo, and one that is too stiff to easily operate. That design window is not necessarily the optimum window for long spring life.

HexHead
February 15, 2015, 06:48 PM
1. What is the difference between conventional and variable recoil springs?
The difference is both physical and operational. With a conventional spring, all the coils are spaced equally apart, except for the closed ends. In a variable recoil spring the space varies between coils with less space between coils at one end and more space between coils at the other end.

The way the two springs store energy is also different. For example if a conventional recoil spring is compressed 1/2", it might store 1 pound of energy. For every additional 1/2" this spring is compressed it would then store 1 additional pound of energy. When a variable recoil spring is compressed 1/2", it might store 1/4 pound of energy. The next half inch of compression might store 1/2 pound, the next half inch might store 3/4 pound and so on. In other words, a conventional spring stores energy on a straight line and a variable spring stores energy on a curve. If both springs are rated at 16 pounds, they will both store 16 pounds when compressed to the same working length, but the way they get to 16 pounds is different.

2. Should I use a conventional or variable spring when both are available?
The choice is often very subjective. Conventional recoil springs are particularly beneficial when shooting heavier loads where keeping the slide closed as long as possible is desired. Variable recoil springs reduce the battery load values with increasingly greater recoil load values. This results in easier unlocking, improved recoil energy storage, dampening, feeding, breaching and lockup. Variable recoil springs are particularly beneficial with compensated pistols and when using light target loads where less recoil energy is available. The "correct type" of recoil spring is best determined through experimentation and your own personal preference.


3. What weight recoil spring should I use with a particular load?
This is a very common but hard question to answer in exact terms and in most cases an exact answer is not possible. There are many factors which influence the correct weight recoil spring to use. These factors include the particular ammunition brand and load, individual pistol characteristics, individual shooting styles and your individual, subjective feeling of how the gun shoots and should feel.

The factory spring weight is designed to operate the pistol with what would be considered average loads, plus or minus a little. It is not uncommon for manufacturers to specify what they consider a factory ammunition load.
In general terms, the heaviest recoil spring that will allow the pistol to function reliably is the best choice - tempered by the above factors. As a rule of thumb, if your spent casings are first hitting the ground in the 3 to 6 foot range, then the recoil spring is approximately correct. If you are ejecting beyond the 6-8 foot range, then a heavier recoil spring is generally required. If your casings are ejecting less than 3 feet, a lighter recoil spring may be needed to assure reliable functioning.

Taking these factors into consideration, it then comes down to how the gun feels and performs when shooting - in your judgment. However, using too light a recoil spring can result in damage to the pistol and possible injury to you.

4. How often should I change my springs?
The performance of your gun is the best indicator of when a spring needs to be replaced. Factors such as increased ejection distance, improper ejection and/or breeching, lighter hammer indents on primers, misfires, poor cartridge feeding from magazines, frequent jams, stove pipes and other malfunctions are all possible indications of fatigued springs or improper springs.

Springs such as magazine springs, striker springs and recoil springs are subjected to higher stress levels and will require more frequent replacement than other lower stressed springs such as firing pin springs and hammer springs.

Wolff springs are made with the highest grade materials and workmanship. Most Wolff [recoil] springs will remain stable for many thousands of rounds. Some recoil springs in compact pistols, especially where dual springs are used or are replaced by a single spring may require changing after 500 - 1500 rounds. Springs that become rusty, bent or otherwise damaged should always be replaced. Again, changes you observe in your firearm's performance are the best indicators that a change is needed.

5. How often should I change magazine spring? Should I unload my magazines, rotate magazines, load with fewer than the maximum rounds?
Magazine springs in semi-auto pistols are one of the most critical springs and are the subject of much debate and concern. Magazines which are kept fully loaded for long periods of time, such as in law enforcement and personal/home defense applications, will generally be subject to more fatigue than the weekend shooter's magazine springs in which the magazines are loaded up only when shooting.

Magazine design and capacity also affect the longevity of the spring. In many older pistol designs, maximum capacity was not the always the goal such as with the 7 round 1911 Colt magazines will last for years fully loaded. There was room for more spring material in these guns which reduces overall stress and increases the usable life of the spring.

More recently higher capacity magazine have become popular. These are designed to hold more rounds with less spring material often in the same space. This puts more stress on the spring and will cause it to fatigue at a faster rate. Unloading these magazines a round or two will help the life of the spring. Rotating fully loaded magazines will also help the problem somewhat but it is not always practical.

In applications where the magazine must be kept loaded at all times, a high quality magazine spring such as Wolff extra power magazine springs, will provide maximum life. Regular replacement of magazine springs will provide the best defense against failure from weak magazine springs. Regular shooting of the pistol is the best way to be sure the springs are still functioning reliably.

6. My spring got shorter after I used it for a short time. Is it bad?
Most new springs will take a set when they are first compressed. That means they will shorten up. This is a normal event and you should not be immediately alarmed. The greater the stress on the spring, generally the more set that will occur. All Wolff springs take this set into consideration. The ratings of the springs you receive are the ratings after the set has occurred. After set has taken place, the spring should remain essentially stable for the life of the spring.

7. My lighter [recoil] spring is longer than the heavier spring for the same gun. Is this a problem?
Wolff offers many springs in different weights for the same use. Factors such as the size of the wire, the number of coils, the outside diameter of the spring as well as the free length determine the strength of a particular spring. Often, lighter springs are longer than heavier springs because lighter wires and/or a different number of coils are used. Free length is then adjusted to achieve the exact strength desired.

8. The spring I purchased is longer than the original spring so I don't think it will fit.
The free length of a spring is not the most important factor in determining whether it will fit. Many Wolff springs are longer than factory springs. This is normal and the spring will fit.

The more important factor in determining whether a spring will fit is the number of coils in the spring times the diameter of the wire. For example, take 2 springs - one is 7 inches long and the other is 4 inches long. If both springs contain the same number of coils and use the same size wire, both springs will compress to the same solid lengths. The strengths will however be quite different but both springs will fit in the same application.


9. What is the difference between a firing pin spring and a striker spring?
A firing pin spring is actually a return spring as it returns and keeps the firing pin retracted. The firing pin spring works in front of the firing pin pushing the firing pin away from the primer usually keeping it retracted in the slide. When the firing pin is struck by the hammer the impact force of the hammer overcomes the retraction force of firing pin spring and drives the firing pin into the primer.
A striker spring is actually the spring that causes the firing pin to striker the primer. The striker spring works behind the firing pin. When the gun is in the cocked position, the striker spring is compressed behind the firing pin. When the trigger is pulled the firing pin is released and the striker spring pushes the firing pin into the primer. While technically incorrect, a striker spring is often referred to as a firing pin spring.
That sounds like the oil change place that says you should change your car's oil every 3000 miles.

Do your car's springs wear out from the weight of your car when it's parked in your driveway?

Jlr2267
February 15, 2015, 06:59 PM
I suspect that there might be a slight difference in design philosophy between someone designing a jet engine with springs in it and someone designing a magazine with a spring in it that can be purchased for about $10 and is easily replaced by an unskilled person in about 1 minute.

There are more similarities than you might think. The real difference is in the amount of resources available to someone designing an engine vs. an air gun, and the confidence in life prediction that each requires.

Since failure is not an option for an engine, big resources are allocated to answer questions about the behavior of materials under various loading conditions. Don't get me wrong, I'm not saying there's nothing more to learn...I'm open to any new failure mechanisms that might be there...I just have not seen them yet and am very skeptical.

Walt Sherrill
February 15, 2015, 07:21 PM
Do your car's springs wear out from the weight of your car when it's parked in your driveway?

Not likely -- as the car's springs aren't compressed to their limits or anywhere near their design limits.

Load about a half-ton of bricks in the trunk and drive it around -- or just let it set in the driveway -- for a few months and see what happens. That test may be the equivalent of keeping a very high-cap mag fully loaded (and its springs very nearly fully compressed) for a long period. Your example above is like saying load a round or two...and let it set. Not much of a test.

CDW4ME
February 15, 2015, 08:26 PM
That sounds like the oil change place that says you should change your car's oil every 3000 miles.

I do change my oil every 3,000 miles, cheap peace of mind.

I change magazine springs if they need it, they're cheap too.

Longhorn 76
February 15, 2015, 08:30 PM
The whole issue about leaving spring piston air guns cocked is a red herring. It damages the seals, not the spring.

Jlr2267
February 15, 2015, 08:40 PM
The whole issue about leaving spring piston air guns cocked is a red herring. It damages the seals, not the spring.
That's good to know. Might have saved me some long-winded bloviation if I'd known that earlier!

PRM
February 15, 2015, 08:48 PM
LEO, with exceptions, are NOT gun USERS or SHOOTERS, but gun CARRIERS. - Walt Sherrill

Please... Where is the scientific data to back this myth up, other than what a second cousin to the third wife's father-n-law said at a 4th of July party at the lake in 1994.

I've been an LEO for 37 years and more officers than not, whom I've worked with are pretty much gun enthusiast, as well as supporters of the 2nd Amendment. They are pretty much a cross section of the community at the low end of the spectrum with most weighing in heavily on the conservative pro-gun side.

short barrel
February 15, 2015, 08:50 PM
I am retired LEO. I was taught to empty magazines every month to release the tension, and that it was unnecessary to keep them unloaded for any length of time; the instruction was to take the rounds out and put them right back in, once per month. I've always done that. I personally have never heard of a magazine going bad due to loss of spring strength.

JohnKSa
February 15, 2015, 10:15 PM
The whole issue about leaving spring piston air guns cocked is a red herring. It damages the seals, not the spring.Leaving an airgun cocked has no effect at all (either theoretically or practically speaking) on the seals. The issue is the metal spring which is why gas-piston airguns (which use the same seals but gas springs instead of metal springs) are often touted as superior to metal spring piston airguns for hunting because they can be left cocked for long intervals with no ill effect.

http://www.crosman.com/discover/airguns/types-of-airguns

NITRO PISTON
A recent innovation introduced by Crosman is the Nitro Pistonョ power plant in which cocking the rifle moves a piston to the rear, but instead of compressing a spring, a gas (nitrogen) in a cylinder is compressed... the option to leave the rifle cocked for extended periods which might cause weakening of a spring.

http://www.airgundepot.com/remington-nitro-piston-air-rifle-sale.html

"These airguns can be cocked for long periods of time without degrading or losing velocity, like steel springs."

http://www.pyramydair.com/s/m/Umarex_Octane_Air_Rifle_Combo_Gas_Piston/3098

"While gas-pistons (also known as gas springs and gas rams) were originally touted as beneficial for airgun hunting since you can leave your gun cocked without fatiguing a metal spring..."

http://www.americanairgunhunter.com/nitro.html

Enter the Gas Spring Piston airgun; the technology has been around for a while now, but only recently is it being offered in a standard production gun. This technology allows the coiled steel mainspring to be replaced with a sealed piston containing a volume of Nitrogen which is further compressed when the gun is cocked, in effect creating a “gas spring”. The gas spring does not provide an increase in the power output when compared to a traditional mainspring, in fact it may decrease a little depending how the gun is set up. But it addressed two of the more serious issues; substantially reducing the felt bidirectional recoil and allowing the gun to be left cocked for long periods of time without damaging the gun.

Walt Sherrill
February 15, 2015, 11:48 PM
I don't think it's necessary to download, and if does anything at all, it would possibly shorten the life. If I've already fully loaded the magazine, downloading 2 rounds does not reduce any damage because there is no further damage occurring when the spring is sitting there loaded. By downloading it, you are actually adding to the fatigue damage (albeit an infinitesimally small amount, most likely).

...Unless that fully loaded mag has compressed the springs beyond the spring's elastic limit, then downloading a round or two will slow the decay/damage process in the same way that rotating mags slows the process. If the spring isn't pushed THAT far, then Wolff's guideline may be an unnecessary step. And if downloading unnecessarily adds only an infinitesimally small amount of fatigue damage, its clearly a harmless guideline.

My reading on this topic suggests that as a coil spring reaches it's elastic limit, the longer it remains in that state, the more damage is done. With coil springs the degradation seems to be a slow process because coil springs tend to spread the work over more material than some other types of springs. As damaged material loses it's ability to work, the work it would have performed is then done by the remaining material. Then some of that remaining material is also pushed to or beyond it's elastic limit, and more material is degraded. It gets worse, but it does so relatively slowly.

I think that explains why most magazine and recoil springs seem to soften rather than break -- it's a gradual process done in little increments. In handguns, we throw out weakened coil springs BECAUSE THEY NO LONGER WORK, and do so long before they ever get to the point where they could break -- their very nature typically prevents breakage.

If you have a mag that pushes its springs to their elastic limit, downloading the mag a round or two will DELAY the inevitable deterioration. The springs don't heal, but they aren't compressed as much and drop away from the limit. That results in a real-world lengthening of spring life. But -- the minute the downloaded rounds are put back in the mag, the slow deterioration resumes...

In the case of the Rohrbaugh R9 recoil spring I mentioned earlier, which seems to be a "sacrificial" spring, leaving the slide locked open for long periods might accelerate the deterioration of that spring as (or more) quickly as cycling the spring -- which kills it pretty quickly.

Walt Sherrill
February 16, 2015, 12:03 AM
Please... Where is the scientific data to back this myth up, other than what a second cousin to the third wife's father-n-law said at a 4th of July party at the lake in 1994.

I've been an LEO for 37 years and more officers than not, whom I've worked with are pretty much gun enthusiast, as well as supporters of the 2nd Amendment. They are pretty much a cross section of the community at the low end of the spectrum with most weighing in heavily on the conservative pro-gun side.

I got my scientific data the same place you got your data.

I have observed friends and family members who are LEO, watched for other LEOs at nearby ranges, and met a few of who were participants in the various gun games. Even according to them, they feel they are the exceptions in their departments. LEOs participate on these forums, and I've bought and sold weapons from/to them, but they seem to be a very small part of the whole. Maybe I'm wrong, but I'm not sure that makes you RIGHT.

That said, one of the best shooters I know was a deputy sheriff for many years -- until he screwed up a knee on the job -- and a couple of his work buddies shot with us from time to time. That was about it.

My son was SWAT for a local PD, and is now a State Trooper. A few of his friends and a few of his coworkers are shooters, but I think I knew far more shooters than he does. (I suspect I shoot more than he does, too.) His fiance is a deputy sheriff and she shoots a couple of times a year -- when she qualifies.

How many in your organization do differently?

Being pro-gun isn't the same as being a gun enthusiast.

Jlr2267
February 16, 2015, 01:00 AM
.Unless that fully loaded mag has compressed the springs beyond the spring's elastic limit, then downloading a round or two will slow the decay/damage process in the same way that rotating mags slows the process.

What decay/damage process are you referring to? What are you suggesting happens while a spring sits in a compressed state? Let's say you load your mag to 1/2 capacity and put it in the safe...what happens now?

danez71
February 16, 2015, 01:16 AM
If you are suggesting that springs can take a permanent set, giving a shorter uncompressed length after being loaded, this is true, but has literally nothing to do with the length of time under load. .


Time absolutely does have an affect. I'm not sure why you would thing otherwise.



http://www.lesjoforsab.com/technical-information/durability.asp

http://www.lesjoforsab.com/technical-information/technical-report0901_id1174.pdf

http://en.wikipedia.org/wiki/Spring_(device)

http://www.engineersedge.com/material_science/yield_strength.htm

http://www.rockfordspring.com/relaxationofsprings.asp

http://springipedia.com/compression-stress-spring.asp

http://www.db-thueringen.de/servlets/DerivateServlet/Derivate-24673/ilm1-2011iwk-064.pdf

JohnKSa
February 16, 2015, 01:28 AM
It absolutely has to do with the amount of time. I'm not sure why you would thing otherwise.Nice links.

From the first one.
One physical phenomenon with metals is that at stress below the yield strength of the material a very slow plastic deformation take place. In the spring branch this is called creep when a spring under constant load loose length and it is called relaxation when a spring under constant compression lose load. How much creep/relaxation is depends on the temperature, the stress in the metal, the metals yield strength and the time. Increased temperature, stress and time also increase the creep/relaxation

From the fifth one.

Most springs are subject to some amount of relaxation during their life span even at room temperature. The amount of spring relaxation is a function of
付he spring material
付he stress the spring is exposed to
付he temperature
付he amount of time the spring is exposed to the higher stresses and temperatures.
...
This relaxation is usually less than 1 or 2% at room temperature, but can be much more when the spring is exposed to higher stresses...
...
A spring held at a certain stress will actually relax more in a given time than a spring cycled between that stress and a lower stress. The reason is that it spends more time at the high stress.

Jlr2267
February 16, 2015, 01:37 AM
Time absolutely does have an affect. I'm not sure why you would thing otherwise

You should actually read the linked articles before posting them.

Only one of them suggests a time dependence at room temperature, and that mention is described as creep. Creep does not occur in any appreciable amount at room temperature, so that suggestion is simply misguided.

If you don't know why I think otherwise, you didn't read this thread either...the entire discussion is about mag springs *at room temperature*

Jlr2267
February 16, 2015, 01:45 AM
Nice links.

From the first one.
One physical phenomenon with metals is that at stress below the yield strength of the material a very slow plastic deformation take place. In the spring branch this is called creep when a spring under constant load loose length and it is called relaxation when a spring under constant compression lose load. How much creep/relaxation is depends on the temperature, the stress in the metal, the metals yield strength and the time. Increased temperature, stress and time also increase the creep/relaxation

From the fifth one.

Most springs are subject to some amount of relaxation during their life span even at room temperature. The amount of spring relaxation is a function of
付he spring material
付he stress the spring is exposed to
付he temperature
付he amount of time the spring is exposed to the higher stresses and temperatures.
...
This relaxation is usually less than 1 or 2% at room temperature, but can be much more when the spring is exposed to higher stresses...
...
A spring held at a certain stress will actually relax more in a given time than a spring cycled between that stress and a lower stress. The reason is that it spends more time at the high stress.
The 1st link refers to creep, which does not occur in mag springs at room temp.

The 5th link refers to relaxation as a function of "higher stresses AND temperature"...another reference to creep.

Please read about creep in metals if you want to understand why it is not significant at room temperature

pockets
February 16, 2015, 07:15 AM
This again?



.

moxie
February 16, 2015, 08:27 AM
Yup. I love the "long winded bloviation."

Walt Sherrill
February 16, 2015, 10:45 AM
What decay/damage process are you referring to? What are you suggesting happens while a spring sits in a compressed state? Let's say you load your mag to 1/2 capacity and put it in the safe...what happens now?

Forgive my underlining, above. I'm referring to the damage that occurs when springs are stressed at or beyond their elastic limit. A spring in a mag that has been loaded to 1/2 capacity would arguably not be affected -- or, to use your term -- affected only infinitesimally.

But a spring in a mag that is FULLY LOADED and uses a spring that is pushed past it's elastic limit will apparently degrade more quickly -- and the longer it's left in that stressed state, the more it will degrade. But it's apparently still a very slow process. Quality springs that aren't pushed to that limit will likely have a long and useful life -- even when the mags are fully loaded. (Springs don't heal, don't get stronger by being left unused, etc. Non-use simply delays the inevitable that comes with use and stress. And stretching springs doesn't restore their lost function -- as has been argued by one participant here, who used to buy and resell mags, after stretching the springs.)

My comments in this discussion, from the very first, were focused on mag springs and recoil springs that are pushed to their limits or beyond because of design objectives.

In some cases, it appears only a certain level of necessary function can be achieved through what I might I the "sacrificial" use of the spring. The recoil spring in the Rohrbaugh R9 seems to be such a spring. Recoil springs for very compact .45s also have a much shorter recommended service life than their full-size counterparts. Other designs that may fall into that category include some of the ultra-hi-cap mag designs. Some springs may now be considered "renewable resources."

In designing the Rohrbaugh R9, that firm apparently traded spring life for easier use. Making the gun slightly larger or the slide slightly heavier wasn't an option -- because then the gun wouldn't meet its design objectives. Using a longer-lived spring that still fit the space available probably would have made it almost impossible to rack by hand. (If I remember correctly, when first introduced the recommended service life for the R9 recoil spring was several hundred cycles greater than it is now; they later lowered the recommended service life, but kept the same spring.)

SIG apparently faced a similar choice when they were trying to upgrade their weapons to handle the .40 and .357 SIG round. When they evaluated the P228, they found that a stronger recoil spring was needed, but that made racking the slide very difficult. I can only guess that because there were so many P228s in the field (for military and LEO contracts) they chose to take a different path. SIG then upgraded the similar P229 with a heavier slide and more robust locking block, but kept the springs relatively the same. The upgraded P229, as I understand it, was the first pistol to handle the 357 SIG round. They kept a 9mm version of the gun which shares the same slide, but not the revised locking block. Rohrbaugh couldn't BEEF up a gun that was designed to be very small and light.

I suspect that some gun designers face the same sort of problem when designing their mags: when they make the spring strong enough to handle a higher capacity, it can make the mag difficult to use (either in loading the mag or stripping rounds when fired). So some designers may trade off spring life for more user-friendly function or easier operation in those hi-cap mags. The same may happen with some mags designed for very small guns -- but which hold more rounds than was the case in the past.

.

Vodoun da Vinci
February 16, 2015, 11:50 AM
All I can add is that I purchased a Beretta 92S before they were adopted by the US military...early 1980's and shot it little. But it was my home defense pistol and all 3 mags were loaded and left loaded continuously.

I sold the gun in 2013 and all three mags functioned flawlessly after having been left loaded sitting in a drawer (all 15 rounds!) untouched except to oil once a year for over 20 years. The mags and springs functioned flawlessly when I sold the gun.

My Father in Law passed away in 2012 and left a few pistols to me. One of them a Colt 1903 Pocket Hammerless that had been carried 'bout the Farm and other places by 3 generations of my Wife's kin as a pocket gun. The gun had one original mag - it was built in 1918. It had been loaded in a desk drawer unfired for about 30 years before my Father in Law passed. I shot that gun with the ammunition in the mag after unloading the mag, checking the gun for slam fires and making sure the safeties worked, reoiling and reloading the mag.

All 8 rounds fired flawlessly. That's my experience with mag springs and leaving them loaded.

VooDoo

danez71
February 16, 2015, 02:18 PM
You should actually read the linked articles before posting them.

Only one of them suggests a time dependence at room temperature, and that mention is described as creep. Creep does not occur in any appreciable amount at room temperature, so that suggestion is simply misguided.

If you don't know why I think otherwise, you didn't read this thread either...the entire discussion is about mag springs *at room temperature*

Actually, it is you that should read the links such as JohnSKa did.

You have already back peddled from saying it doesn't matter and leave them loaded as long as you like to conceding to Walt examples of your statement being accurate.

I've provided a LOT of factual data here and on TFL with links to sources and reference material.

You have provided nothing except to say you've spent a lot of you companies money and back peddle your statement.

FYI - I come from one of those industries you mentioned earlier.

You're wrong... we learned a long time ago that springs under constant load can negatively impact their performance.

Also.... it just so happens that guns, when used, heat up past room temp which accelerates things.

If it's only a matter of cycling that wears a spring, why don't we see these questions about replacing recoil springs 20 times more often than mag spring questions?

Because theres a lot more to this issue than repeating 1\2 truths and misunderstandings.

Jlr2267
February 16, 2015, 02:57 PM
Actually, it is you that should read the links such as JohnSKa did.

You have already back peddled from saying it doesn't matter and leave them loaded as king as you like to conceding to Walt examples of your statement being false.

I've provided a LOT of factual data here and on TFL with links to sources and reference matwrial.

You have provided nothing except to say you've spent a lot of you companies money and back peddle your statement.

FYI - I come from one of those industries you mentioned earlier.

You're wrong... we learned a long time ago that springs under constant load can negatively impact their performance.

Also.... it just so happens that guns, when used, heat up past room temp which accelerates things.

If it's only a matter of cycling that wears a spring, why don't we see these questions about replacing recoil springs 20 times more often than mag spring questions?

Because theres a lot more to this issue than repeating 1\2 truths and misunderstandings.

I don't believe I have backpeddled at all. Your links refer to *creep*, which *is not a factor at room temperature*...period, or even at 2,3,400F in steel springs. You have a serious misunderstanding of the fundamentals involved, and have proven so by posting links which don't say what you think they say.

Steel magazine springs *do not creep to any significant degree at their normal service temperatures*...if you disagree, I suggest you take a basic course in engineering fundamentals.

http://en.wikipedia.org/wiki/Creep_%28deformation%29
"the effects of creep deformation generally become noticeable at approximately 30% of the melting point (as measured on a thermodynamic temperature scale such as Kelvin or Rankine) for metals"

http://www.engineersedge.com/material_science/creep.htm "At room temperature, structural materials develop the full strain they will exhibit as soon as a load is applied"

http://weldingdesign.com/consumables/understanding-creep-resistance "Creep only happens at high temperatures (around 900 degrees F and higher for stainless steels)."

http://www.nationalboard.org/Index.aspx?pageID=181 Common steel creep threshold temperatures:
"Carbon steel.......................800oF
Carbon + 1/2 Molybdenum............850oF
1-1/4 Chromium-1/2 Molybdenum......950oF
2-1 /4 Chromium-1 Molybdenum.......1000oF
Stainless steel....................1050oF"

The list is literally endless, and includes every textbook ever written on the subject...please take some time to learn about it.

And no, mag springs get nowhere near these temperatures.

For goodness sake, if you don't believe the links, or me, go ask any metallurgist on the planet that you do trust. You will get *the same answer.*

Ohio Gun Guy
February 16, 2015, 03:07 PM
Here's my relatively cheap solution. I see the above and am personally not sure....

In practice here's what I do.

I buy spare magazines for my auto's (At least the ones that have a job...) I want the extra magazines any way, so I split the Use between 4 magazines (Load 2).

danez71
February 16, 2015, 03:23 PM
I don't believe I have backpeddled at all. Your links refer to *creep*, which *is not a factor at room temperature*...period, or even at 2,3,400F in steel springs. You have a serious misunderstanding of the fundamentals involved, and have proven so by posting links which don't say what you think they say.

Steel magazine springs *do not creep to any significant degree at their normal service temperatures*...if you disagree, I suggest you take a basic course in engineering fundamentals.

http://en.wikipedia.org/wiki/Creep_%28deformation%29
"the effects of creep deformation generally become noticeable at approximately 30% of the melting point (as measured on a thermodynamic temperature scale such as Kelvin or Rankine) for metals"

http://www.engineersedge.com/material_science/creep.htm "At room temperature, structural materials develop the full strain they will exhibit as soon as a load is applied"

http://weldingdesign.com/consumables/understanding-creep-resistance "Creep only happens at high temperatures (around 900 degrees F and higher for stainless steels)."

http://www.nationalboard.org/Index.aspx?pageID=181 Common steel creep threshold temperatures:
"Carbon steel.......................800oF
Carbon + 1/2 Molybdenum............850oF
1-1/4 Chromium-1/2 Molybdenum......950oF
2-1 /4 Chromium-1 Molybdenum.......1000oF
Stainless steel....................1050oF"

The list is literally endless, and includes every textbook ever written on the subject...please take some time to learn about it.

And no, mag springs get nowhere near these temperatures.

For goodness sake, if you don't believe the links, or me, go ask any metallurgist on the planet that you do trust. You will get *the same answer.*

You should read past the 1st few sentences of the links you post. It contridicts a lot of what you say. Time affects creep too.

Jlr2267
February 16, 2015, 03:36 PM
You should read past the 1st few sentences of the links you post. It contridicts a lot of what you say. Time affects creep too.

No kidding? "Time affects creep too"...????????

You do realize that creep *is by definition* time dependent deformation in materials, right?

Please be specific (as I was) as to what is contradicted? What is stated in any of those articles that contradicts the very simple and concise point that:

*creep in steels is not significant at the temperatures where ammunition magazines operate*

You can easily falsify the above statement by either:

1) showing that mag springs get up to 700F in service

or

2) showing that creep in steels is significant at much lower temperatures

Walt Sherrill
February 16, 2015, 04:43 PM
If you don't know why I think otherwise, you didn't read this thread either...the entire discussion is about mag springs *at room temperature*

Actually the entire discussion has been about mag and recoil springs with scant attention paid to temperature. It's not been an important point of focus. The phrase "at room temperature" was seldom mentioned and has NEVER been a key part of any of the comments I've made in this discussion. (I don't think I've ever mentioned it...) I can understand how a recoil spring COULD get pretty warm, with use, but not so warm as to affect the temper/strength of the metal. A gun THAT hot is not a gun I want to hold in my hand. I did NOT consider it a point of discussion.

I apparently misunderstood an important point about spring compression, and you set me straight. You said, in effect, that depressing a spring by physical displacement (using light plastic round replicas) will have the same effect on the spring as using heavier or actual rounds, as long as the springs are compressed to the same degree. If that happens -- i.e., the compression is the same -- the effect is the same.

Except for that misunderstanding (ignorance, really) on my part, the discussion has been focused on the effect of compression (or, arguably, OVER-compression) when the springs are near (or have exceeded) their elastic limit.

With coil springs, I would assume that "elastic limit" should really be considered "elastic limits," as the work is spread over many different places in the spring material. And, because MOST mag springs aren't pure coils, but hybrids, with long flat stretches of material connected to coil arcs and smaller flat stretches. It seems that these springs might act a bit like flat springs AND coil springs, and maybe with some torsion bar-like action thrown in at the corners. Recoilo springs are more typical coil springs.

Given all of that, I would expect degradation to be occur around the various corners in a mag spring, but not occur uniformly or simultaneously throughout the material. It could be a very slow process, and not even noticeable at first. With a recoil spring I might expect to see degradation to occur where compression first occurs... But, maybe I have all of that wrong, too. It won't be the first time I've had it all wrong. I've learned a lot from these discussions, and it seems worth the effort.

danez71
February 16, 2015, 05:15 PM
No kidding? "Time affects creep too"...????????

You do realize that creep *is by definition* time dependent deformation in materials, right?

Please be specific (as I was) as to what is contradicted? What is stated in any of those articles that contradicts the very simple and concise point that:

*creep in steels is not significant at the temperatures where ammunition magazines operate*

You can easily falsify the above statement by either:

1) showing that mag springs get up to 700F in service

or

2) showing that creep in steels is significant at much lower temperatures

Be specific...?

The picture/graph in your 2nd link has "time" and "strain" on the horizontal and vertical lines. Note: temperature in NOT part of the graph because the graph represents what happens with creep at "operating temp".

Eventually, if you compress a spring long enough, the molecules will start to realign and a spring will find its new equilibrium point. That might take 1000 yrs. Or it could take a few days.

However, other things such as temp, material, and how far it's compressed into its elastic range Influence how much Time it will take.

If you don't grasp that, you won't grasp anything else on the topic.

For giggles... what Temps do you think the recoil spring and mag spring see? What are you basing your info on?

I see you're now using qualifying words like "significant" and "properly designed" as a way to give yourself wiggle room.

What you also don't know is if the mfg decided that a spring is a consumable item and crammed more rounds into a smaller mag and thus compressing the spring deeper into its elestic range and shortening its life.

So, please tell us, how much creep, fatigue etc etc does it take to be "significant" enough to have an affect on performance of a mag spring for a glock... or a S&W... or Taurus?

As soon as you can define that, then you can start talking absolutes.

Jlr2267
February 16, 2015, 05:20 PM
Actually the entire discussion has been about mag and recoil springs with scant attention paid to temperature. It's not been an important point of focus.

The phrase "at room temperature" was seldom mentioned and has NEVER been a key part of any of the comments I've made in this discussion. (I don't think I've ever mentioned it...) I can understand how a recoil spring COULD get pretty warm, with use, but not so warm as to affect the temper/strength of the metal. A gun THAT hot is not a gun I want to hold in my hand.

I apparently misunderstood an important point about spring compression, and you set me straight. You said, in effect, that depressing a spring by physical displacement (using light plastic round replicas) will have the same effect on the spring as using heavier or actual rounds, as long as the springs are compressed to the same degree. If that happens -- i.e., the compression is the same -- the effect is the same.

Except for that misunderstanding (ignorance, really) on my part, the discussion has been focused on the effect of compression (or, arguably, OVER-compression) when the springs are near (or have exceeded) their elastic limit.

With coil springs, I would assume that "elastic limit" should really be considered "elastic limits," as the work is spread over many different places in the spring material. And, because MOST mag springs aren't pure coils, but hybrids, with long flat stretches of material connected to coil arcs and smaller flat stretches. It seems that these springs might act a bit like flat springs AND coil springs, and maybe with some torsion bar-like action thrown in at the corners. Recoiil springs are more truly PURE coil springs.

Given all of that, I would expect degradation to be occur around the various corners in a mag spring, but not occur uniformly or simultaneously throughout the material. It could be a very slow process, and not even noticeable at first. But, maybe I have all of that wrong, too. It won't be the first time I've had it all wrong. I've learned a lot from these discussions, and it seems worth the effort.

My 2nd post mentioned "temperatures where magazine springs operate". For all practical purposes, there is no difference in "room temperature" and, say, 500F when discussing creep in steels. I think that range more than covers the expected service temperatures. "Room temperature" is, for me, easier to reference than "temperatures where magazine springs operate".

You are correct that the high stress areas in a spring (bends, corners, etc.) can exceed the elastic limit, and this is in fact what causes springs to take a "set". This can be exacerbated by residual stresses (from machining, heat treating, coating, etc). It can take several load cycles to reach a stable spring length. In a properly designed spring this " set" would be minimized by pre-setting.

However, exceeding the elastic limit results in plastic deformation *immediately* and that plastic strain does not increase with time (unless at elevated temperature, like 700F). If at elevated temperature, plastic strain *will* accumulate over time at much lower stress (this is known as creep).

This is the critical point, and where we keep talking past each other: at these low temperatures, there is no significant creep possible. If there is permanent deformation occurring, one which does in fact depend on the length of time the spring is compressed, there is *something else* going on which has not yet been explained either here, or in the academic literature.

Jlr2267
February 16, 2015, 06:02 PM
Be specific...?

The picture/graph in your 2nd link has "time" and "strain" on the horizontal and vertical lines. Note: temperature in NOT part of the graph because the graph represents what happens with creep at "operating temp".

Um, no. The plot is a generic representation of how creep strain accumulates over time...it's not even real data, just a schematic. You won't find one that shows creep data below 700F...guess why...

I fail to see how the plot contradicts anything



Eventually, if you compress a spring long enough, the molecules will start to realign and a spring will find its new equilibrium point. That might take 1000 yrs. Or it could take a few days.

1000 years...maybe (although very unlikely)....a few days, no.
Look up the diffusion equation for metals and calculate how long your realignment takes at 100F...you'll be surprised

And as an FYI, molecules don't " realign" in creep...grain boundaries slip, dislocations and vacancies migrate through the material to reach a lower energy state. The time required for this diffusion however is astronomical at low temperatures (like where mag springs live)


However, other things such as temp, material, and how far it's compressed into its elastic range Influence how much Time it will take.

If you don't grasp that, you won't grasp anything else on the topic.

Fortunately for you I do grasp that, seeing as how I am paid to incorporate those considerations into the jet engines that carry you and your family around the world.


For giggles... what Temps do you think the recoil spring and mag spring see? What are you basing your info on?


Since the topic is mag springs, I would estimate that they would rarely (if ever) see anything more than 200F, based on my own experience. Did you giggle?


I see you're now using qualifying words like "significant" and "properly designed" as a way to give yourself wiggle room.


I am qualifying my statements because I actually know what I'm talking about, and understand the subtleties involved. A competent engineer understands that "significant" means "to a degree which would affect function." Is that good enough or do you need more definition?


What you also don't know is if the mfg decided that a spring is a consumable item and crammed more rounds into a smaller mag and thus compressing the spring deeper into its elestic range and shortening its life.

What a manufacturer does has no impact on physics. Steels do not creep in any *significant* way at these temperatures. Overloading a spring can certainly shorten its life, but creep has no part in that.


So, please tell us, how much creep, fatigue etc etc does it take to be "significant" enough to have an affect on performance of a mag spring for a glock... or a S&W... or Taurus?


If your asking how much creep strain is significant, the exact answer to that question requires FEA, along with product testing (which, by the way, I can assure you was not done by any gun manufacturer because they, unlike you, understand that creep is not a concern with mag springs).

In general, however, I have found that plain carbon steel springs (1095 for example), do not see a degradation even at 500F for 20000 hours. If you were experienced in dealing with parts that do in fact creep, you'd understand that the time required to creep even an infinitesimal amount becomes astronomical at room temperature.

Walt Sherrill
February 16, 2015, 08:06 PM
You are correct that the high stress areas in a spring (bends, corners, etc.) can exceed the elastic limit, and this is in fact what causes springs to take a "set". This can be exacerbated by residual stresses (from machining, heat treating, coating, etc). It can take several load cycles to reach a stable spring length. In a properly designed spring this " set" would be minimized by pre-setting.

So, that could explain the initial set seen with some springs. The "set" is a source of concern for folks replacing their first recoil spring -- as the new spring is always longer than the one in the gun! :eek: Magazine springs, with bends and corners certainly demonstrate that change. (You have only to buy a new Glock mag to experience it firsthand.) But so do recoil springs which either 1) don't have bends and corners, or are 2) ALL bends and corners....

Neither does it explain the softening of springs that can be observed in the examples that JohnKSa cited -- and which some of us have seen in our own weapons and mags.

John's test examples are not being CYCLED -- the springs are just being kept under a constant load/degree of compression as might be done with long-term storage of ammo in a high-cap mag. Earlier in our discussion you made the point that springs in that state weren't really working, and I think you said that such springs should not deteriorate because they aren't doing anything to cause degradation. That doesn't seem to be what's happening with John's examples, and it's seems more pronounced with the Ruger springs than the Glock. Neither of those makers have mags known for failures -- and I don't think I've ever had to replace a Glock mag spring. But that test isn't complete.

Your comments cited above also do not explain why a Rohrbaugh R9 recoil spring has a recommended service life of only 250 cycles. If the recoil spring takes a set after a relatively few cycles, why do some springs (like the R9 spring) fail later -- after several hundreds of rounds rather than several thousands of rounds as might be the case with the springs in larger guns?

I continue to argue that some springs aren't supposed to have a long life, but are intended to have a shorter life so that they can do more with less material. These springs don't work as long as other springs, but their design allows allows them to do more with less material/in less space -- a critical trait in many of the newer gun designs.

I have also stated that there may be things that can be done with some of these (arguably) sacrificial springs that will lengthen their service life. You seem to disagree -- primarily, it seems, because you don't seem believe that many of the hi-cap mags in question have the potential to degrade under normal usage (which includes long-term storage.)

You've mad a number of comments in this discussion that I've found particularly helpful. I appreciate them. But you also have shown a tendency to "argue from authority" when someone disagrees -- saying, in effect, "I'm an expert and you should believe me -- I know more than you do." You may, in fact, know more than many of us do, but that SORT of proof isn't very convincing.

You might want to try a different approach.

Jlr2267
February 16, 2015, 08:09 PM
That might take 1000 yrs. Or it could take a few days.

Actually, the 1000 yrs is not a bad estimate, if you're at 300F, holding it at the material's yield strength.

Here are the numbers for ASTM A516 steel (extrapolated of course), for time to reach 0.2% creep strain (which is a very small amount of creep by the way), when loaded to the elastic limit:

T(F), hours, days, years,
800, 2.05E+01, 8.53E-01, 2.34E-03
700, 2.98E+02, 1.24E+01, 3.40E-02
600, 1.79E+03, 7.45E+01, 2.04E-01
500, 3.56E+04, 1.48E+03, 4.06E+00
400, 5.38E+05, 2.24E+04, 6.14E+01
300, 8.37E+07, 3.49E+06, 9.56E+03
200, 6.81E+10, 2.84E+09, 7.78E+06
100, 5.56E+14, 2.32E+13, 6.35E+10

note that loading to the yield strength at 300F and holding it there, essentially baking in your oven at 300F, would require 956 years to get even 0.2% creep. I couldn't afford that test. At 100F, which is a much more reasonable estimate for the magazine spring temperature for the vast bulk of it's life, the time is 63.5 billion years.

So yeah, you'd better hurry and unload your magazine before it creeps beyond all repair

Jlr2267
February 16, 2015, 09:59 PM
So, that could explain the initial set seen with some springs. The "set" is a source of concern for folks replacing their first recoil spring -- as the new spring is always longer than the one in the gun! :eek: Magazine springs, with bends and corners certainly demonstrate that change. (You have only to buy a new Glock mag to experience it firsthand.) But so do recoil springs which either 1) don't have bends and corners, or are 2) ALL bends and corners....

Neither does it explain the softening of springs that can be observed in the examples that JohnKSa cited -- and which some of us have seen in our own weapons and mags.

John's test examples are not being CYCLED -- the springs are just being kept under a constant load/degree of compression as might be done with long-term storage of ammo in a high-cap mag. Earlier in our discussion you made the point that springs in that state weren't really working, and I think you said that such springs should not deteriorate because they aren't doing anything to cause degradation. That doesn't seem to be what's happening with John's examples, and it's seems more pronounced with the Ruger springs than the Glock. Neither of those makers have mags known for failures -- and I don't think I've ever had to replace a Glock mag spring. But that test isn't complete.

Your comments cited above also do not explain why a Rohrbaugh R9 recoil spring has a recommended service life of only 250 cycles. If the recoil spring takes a set after a relatively few cycles, why do some springs (like the R9 spring) fail later -- after several hundreds of rounds rather than several thousands of rounds as might be the case with the springs in larger guns?

I continue to argue that some springs aren't supposed to have a long life, but are intended to have a shorter life so that they can do more with less material. These springs don't work as long as other springs, but their design allows allows them to do more with less material/in less space -- a critical trait in many of the newer gun designs.

I have also stated that there may be things that can be done with some of these (arguably) sacrificial springs that will lengthen their service life. You seem to disagree -- primarily, it seems, because you don't seem believe that many of the hi-cap mags in question have the potential to degrade under normal usage (which includes long-term storage.)

You've mad a number of comments in this discussion that I've found particularly helpful. I appreciate them. But you also have shown a tendency to "argue from authority" when someone disagrees -- saying, in effect, "I'm an expert and you should believe me -- I know more than you do." You may, in fact, know more than many of us do, but that SORT of proof isn't very convincing.

You might want to try a different approach.
I can't explain every spring experiment result, carried out in every garage across America. I can only say definitively that creep is not the cause of the degradation you see.

As for my "argument from authority"... I will strongly disagree. I clearly explained (or tried to) the physics and made definitive statements which can be easily falsified (if false). Moreover, I explicitly stated more than once that I am open to a physics based explanation of this degradation phenomenon...and I'm still waiting by the way. The fact that creep is essentially nonexistent at these temperatures is fairly common knowledge, and it is not an argument from authority to state that the sky is blue...anyone can look out their window, and anyone can use the internet to learn creep basics in 5 minutes or less...really, it's not some esoteric specialty. An argument from authority would be spamming a thread with links to info which one does not understand, while expecting others to believe it *just cause its on the net*

danez71
February 16, 2015, 10:29 PM
This little know organization talks about it happening

http://www.astm.org/DIGITAL_LIBRARY/MNL/SOURCE_PAGES/DS60_foreword.pdf



An example of this relaxation limit is given in
Figure 2 for an annealed Type 304 stainless steel for
which Tm is about 800 deg. F. The remaining stress
reaches a limiting value within 100 hours for temperatures
up to 600 F (315 C) and 90% of this relaxation
takes place within 24 hours. The remaining stress is
given in Figure 2 as a function of the initial stress.
This material at room temperature has significant
relaxation which decreases with the initial stress.




Or..

http://www.db-thueringen.de/servlets/DerivateServlet/Derivate-24673/ilm1-2011iwk-064.pdf

To investigate relaxation, the springs are loaded to the prescribed relaxation tension and stored in this state at the given relaxation temperature for the given time.

At the end of this time, the load is taken off the springs and the spring force and length at the given working point again measured.

This method provides the details of both the shortening and the reduction in force which are due to the relaxation.



Relaxation temps were 20C (about 68F aka room temp) 80C, and 160C

10270-2-FDSiCr spring steel wire.

wire diameters:1 mm, 3 mm and 6 mm

tempered to 350C and 450C.


2% degradation at 20C/68F/room temp in as little as ~70 hrs. (I think that was the 1mm wire)




Or.... one can look out their window and realize that the biggest reason why pianos need to be re-tuned fairly often is because of the spring steel wire stretches at room temperature.

Jlr2267
February 16, 2015, 11:42 PM
This little know organization talks about it happening

http://www.astm.org/DIGITAL_LIBRARY/MNL/SOURCE_PAGES/DS60_foreword.pdf



Thank you. This paper makes it very clear that *creep* is not the cause of relaxation at low temperatures.

More interestingly, it discuss something which may offer a possible explanation for room temperature stress relaxation in 300 series stainless steels, which may be what some folks here claim to have observed. Anelastic strain, which increases over a short period of time after load, but is recovered on load reversal.

This may actually be unique to austenitic steels, as they tend to have an ill-behaved modulus line, they strain harden like crazy, and are generally a PITA to characterize. Note that chart 1 has no data below about 700F.

I'm skeptical, however, since the paper says 304 steel has a Tm of 800F...which is an *obvious* error. Either they used another material, or they stated the wrong melting point. Either way, obvious errors like this strain credibility.

And there are other problems with paper as well, for example:

Figure 2 suggests that at room temperature, an initial stress of 24 ksi (which is ~80% of annealed 304's yield stress) relaxes to 17 ksi within 100 hours as stated in section 4.1: "The remaining stress reaches a limiting value within 100 hours for temperatures up to 600 F." This means the stress has relaxed 29% within 100 hours, at room temperature, when loaded to 80% of yield strength.

Compare the above result to the information from figure 3. This figure says that the material (cold worked 304) is loaded to "an initial inelastic strain of 0.07%." So the material represented in this plot is loaded to ~85% of its yield stress, at 900F, yet in 100 hours only relaxes about 15%.

These 2 plots therefore lead to the conclusion that stress relaxation is more severe at room temperature than at 900F! This is, of course, nonsense.

These errors in the paper lead me to the conclusion that the material represented by figure 2 very well may not be 304 steel.


http://www.db-thueringen.de/servlets/DerivateServlet/Derivate-24673/ilm1-2011iwk-064.pdf


Relaxation temps were 20C (about 68F aka room temp) 80C, and 160C

10270-2-FDSiCr spring steel wire.

wire diameters:1 mm, 3 mm and 6 mm

tempered to 350C and 450C.


2% degradation at 20C/68F/room temp in as little as ~70 hrs. (I think that was the 1mm wire)



2% relative force reduction, not attributed to *creep*...the maximum reduction at the longest time recorded was 3% for room temperature...also not creep, and also not *significant*...no spring is designed so close to its functional specification that it cannot tolerate a 3% force reduction


Or.... one can look out their window and realize that the biggest reason why pianos need to be re-tuned fairly often is because of the spring steel wire stretches at room temperature.

Yes, they stretch at room temp, they experience high frequency vibrations which contribute greatly to that, BUT they do not *creep* at room temperature. A *tiny* amount of stretch can be *significant* in a piano string (changes the pitch), but we are talking mag springs, not piano wire.

Walt Sherrill
February 16, 2015, 11:49 PM
I can't explain every spring experiment result, carried out in every garage across America. I can only say definitively that creep is not the cause of the degradation you see.

I don't think I've ever mentioned CREEP, and you didn't get into this discussion until it had been going for quite a while. At post #50, you and I seemed to be almost in agreement. Others took the discussion elsewhere.

The degradation I see is -- and I acknowledge my limited knowledge of the proper terms -- is probably permanent deformation -- the state a solid exhibits when it's elastic limit has been exceeded. That is what seems to be happening with some hi-cap mags. That's also probably what's happening with the Rohrbaugh R9 recoil springs I mentioned. It may be what's happening in JohnKSa's tests. I suspect that's what happens when a coil spring softens with use, over time. And that is, I suspect, what Wolff Springs guideline is intended to postpone or delay -- through downloading a round or two. They may suspect that SOME springs are sacrificial. But if a downloaded spring isn't sacrificial, downloading won't really hurt; if it is sacrificial (when fully loaded), downloading will postpone the inevitable.

You've said that unless a spring is working, things can't change. I wonder: if a spring is depressed far enough to exceed the spring materials elastic limit, and the spring material starts to permanently deform, doesn't THAT become a subtle form of work? (If it's NOT work, why is it damaging the material? Is some minimal amount of cycling required before permanent deformation can occur? That may be the part I'm overlooking...)

I suspect that the longer a magazine spring or recoil spring is subjected to the stress that causes the spring material to exceed it's elastic limit, then more and more of the springs material will be deformed as the remaining material experiences the same stress/work/pressure, etc. that was once handled by a greater supply of non-deformed material.

I don't think that permanent deformation happens instantly or uniformly throughout the material, and as you've noted in earlier replies, loading and working the spring puts different loads on different parts at different times. Cycling the springs does the same, as will reloading the mag before it is completely empty, etc. Many, many variables can affect what happens.

Do coil springs soften or just break? (I'm not trying to force an either/or choice, there. Answer however you like.)

Bill DeShivs, a knifemaker who talks of his experience making springs, says properly made springs should break, not soften, and then only from being worked. What's YOUR position on that point? Bill doesn't seem to embrace the concept of springs made to work well for shorter periods (i.e., sacrificial springs.)

How does failure in a coil spring manifest itself if it does fail (for whatever reason)?

Jlr2267
February 17, 2015, 02:39 PM
Do coil springs soften or just break? (I'm not trying to force an either/or choice, there. Answer however you like.)



They can do either, or both, depending on the conditions of temperature history, load history and material properties.

When springs develop microcracks, they can "soften" because the cracks lower the effective modulus of the material. These cracks can grow, coalesce and eventually the spring breaks.

One of the links posted by danez71 suggests that there can be a small amount of room temperature stress relaxation at very high stress (relative to yield strength), which would "soften" a spring. For the application of a magazine spring however, 2-3% loss in spring force would seem to me insignificant.

Mechanical compression springs are generally designed to be at only a fraction of yield strength when fully compressed (40% is a generic upper limit). In critical applications, they are also "preset". My guess is that mag springs are not designed as critical components and are somewhat of an afterthought.

danez71
February 17, 2015, 03:44 PM
One of the links posted by danez71 suggests that there can be a small amount of room temperature stress relaxation at very high stress (relative to yield strength), which would "soften" a spring. For the application of a magazine spring however, 2-3% loss in spring force would seem to me insignificant.

Mechanical compression springs are generally designed to be at only a fraction of yield strength when fully compressed (40% is a generic upper limit). In critical applications, they are also "preset". My guess is that mag springs are not designed as critical components and are somewhat of an afterthought.


Thats the point that Walt, and then me, we're pointing out a couple of pages ago and you refused to acknowledge.

Regardless, I'm glad we've come full circle in under 4 pages.:)

3% may be significant in some designs... I don't know and I'm not going to spend the time to figure it out.

However, making a blanket statement saying all mags can be loaded full indefinately and have no negative effects is not accurate.

You mentioned 40% above. I can say with some authority that Hughes uses 25% for many space applications with "indefinately" as the life span goal.

It can be done with springs.... but all mag spring aren't designed with the same level of safety margin as is designed into flight and space applicatons.

GLOOB
February 17, 2015, 04:02 PM
That's also probably what's happening with the Rohrbaugh R9 recoil springs I mentioned.
Rohrbaugh states that the spring should be replaced every 250 cycles? Do they make any mention of how LONG you can leave a magazine loaded before replacing the spring?

I think the Rohrbaugh mag would be a perfect garage experiment to see how leaving a "sacrificial spring" loaded affects its performance.

It would be pretty lame if a Rohrbaugh could only be loaded for, say, 7 days at a time, lol. So to me, it seems like the R9 example is supporting what Jlr2267 has been saying all along. Replace after # cycles, not amount of time.

Also, re: piano example. The biggest reason for pianos going out of tune is probably warping of the wood frame, don't you guys think?!

Jlr2267
February 17, 2015, 04:26 PM
However, making a blanket statement saying all mags can be loaded full indefinately and have no negative effects is not accurate.
.

Well, I do concede that there is some amount stress relaxation, even at room temperature. I do however think the available data suggests it is limited to roughly 1%-5%, which shouldn't be significant in a robust design (but then again mag springs are probably not that well thought out).

My apologies if I came across as a pompous a-hole...not my personality at all...just let the frustration get to me.

GLOOB
February 17, 2015, 04:38 PM
They way I see it, it may be a good thing to leave a mag loaded for an extended period when you first get it.

If the spring was not thoroughly tempered, and you let the stress relaxation occur through use, the spring will start to give at one specific spot, first. The rest of the spring is still "stronger" with the "new spring feel" than the initial "weakest link," hence that point will bend more than the others as you are loading the mag. Do you want to repeatedly cycle that mag partway (by downloading it) many times before the entire spring has relaxed? Repeatedly "aging" one point faster than the rest of the spring? Or do you want to let it sit at maximum compression until the whole spring is destressed? If you download it by one or two, you're only bending a couple of points on that spring all the way (or possibly even more than all the way!), and the rest won't begin to "take a set" until you load it all the way for the first time.

Ideally, the spring will be thoroughly heat tempered before it is installed, which will destress the entire spring, equally. But if it's not tempered enough, you could get into the above situation maybe? To me, this must surely be one of the reasons you need to temper a spring to begin with. Otherwise, you could just use if right away (albeit at a higher initial weight), and eventually the stresses would be relieved over time, at room temperature. But this is not the case... what happens is the spring is more prone to breaking - through repeated cycling, NOT from sitting still.

I dunno. I know that I leave my mags loaded fully. If that makes them stop working, I want to know sooner rather than later. If my mags don't work after fully "taking a set," I will figure out what springs and how many rounds WILL work for those mags, I guess. If I'm going to download a mag, it's because I am going to do so ALL the time. Not just for storage.

Jlr2267
February 17, 2015, 05:09 PM
They way I see it, it may be a good thing to leave a mag loaded for an extended period when you first get it.

If the spring was not thoroughly tempered, and you let the stress relaxation occur through use, the spring will start to give at one specific spot, first. The rest of the spring is still "stronger" with the "new spring feel" than the initial "weakest link," hence that point will bend more than the others as you are loading the mag. Do you want to cycle that mag many times before the entire spring has relaxed? Repeatedly over-bending and potentially fatiguing that point? Or do you want to let it sit at maximum compression until the whole spring is destressed? If you download it by one or two, you're only bending a couple of points on that spring all the way, and the rest won't "take a set" until you load it all the way for the first time.

Ideally, the spring will be thoroughly heat tempered before it is installed, which will destress the entire spring, equally. But if it's not tempered enough, you could get into the above situation maybe? To me, this must surely be one of the reasons you need to temper a spring to begin with. Otherwise, you could just use if right away (albeit at a higher initial weight), and eventually the stresses would be relieved over time, at room temperature. But this is not the case... what happens is the spring is more prone to breaking - through repeated cycling, NOT from sitting still.

I dunno. I know that I leave my mags loaded fully. If that makes them stop working, I want to know sooner rather than later. If my mags don't work after fully "taking a set," I will figure out what springs and how many rounds WILL work for those mags, I guess.
I've never replaced a spring on mags I keep loaded like my HD guns (loaded for 16 years, shot very little). I have frequently replaced springs in various range gun mags however (lots of loads/unloads).

moxie
February 17, 2015, 05:12 PM
Some non-scientific observations:
1. While I personally have never had a magazine spring (rifle or pistol) fail due to being fully loaded for an extended period, it's clear from many of the posts in this and other threads that it does seem to happen. What's missing is any analysis of make, model, type of gun/mag/spring, time loaded, etc. So all we've got is a lot of anecdotes. Take away seems to be: if you've got a weak spring, change it.

2. Here's a war story for your reading pleasure. In Vietnam, for perceived safety reasons many Army armories stored 1911s with slides locked to the rear hanging on wood pegs through the trigger guard. This obviously kept the recoil springs smashed pretty tight, often for long periods. I fired some of these guns and was plagued with a lot of failures to go into battery. A tap on the back of the slide fixed the problem. Clean guns, well lubed, GI ammo. I figured out it was the recoil springs. You could feel they were wimpy when racking the slides. Changed them out and voila! No more failures. This is obviously not a scientific experiment but does show anecdotally that some coil springs do lose their springiness (there's physics for ya) when kept squashed for a while. I have no idea whether mag springs (all/some) are made the same as recoil springs (all/some) and thus prone to the same vicissitudes.

GLOOB
February 17, 2015, 05:31 PM
I think my post #90 can explain why springs seem to take more set over a longer period of compression.

In a mag, the spring is not compressed quite all the way, to the point where each coil is physically resting on top of the other (otherwise the mag wouldn't fit in the gun; well, maybe some 8 rd 1911 mags are an exception. :)). The weight of the spring is not exactly the same across it's entire length, and any residual stress will take time to resolve.

So at first, when fully loaded, there are some points on the spring that are bent more than others, due to asymmetrical distressing of the entire coil. So when you remove the spring, it's longer, because some parts of that spring are still not distressed all the way. Over enough time under compression, the distribution may become more even, and more of the spring will be fully distressed? This is simply the initial distressing of the spring, not creep, I guess. I'm a little out of my depth in this discussion.

danez71
February 17, 2015, 07:01 PM
This is in response to post89 by Jlr2267

I totally agree.

I think mags for service pistols designed for military will more than likely have enough margin built in to not be affected by 3%. Compacts and micro designs is when things gets sketchy.

For the record, I've never changed a mag spring.

Pompous a-hole? Maybe a little ;) ... but we all have it in us. Maybe I just stumbled a new friend.:)



I've been using my phone the last couple days to post so that explains 1\2 my screw ups and typos.

Walt Sherrill
February 17, 2015, 07:55 PM
They can do either, or both, depending on the conditions of temperature history, load history and material properties.

When springs develop microcracks, they can "soften" because the cracks lower the effective modulus of the material. These cracks can grow, coalesce and eventually the spring breaks.

That makes sense, and it probably explains why we don't see many broken coils springs in handguns -- because if they get soft and they don't perform well, they will be discarded BEFORE the cracks can grow, coalesce, and the spring material break. (Car coil springs may be different, because a car can still drive with weak, maybe slightly sagging springs. They can carry heavy loads and hit big bumps, etc.. for a long time... and then they can break! :p )

Mechanical compression springs are generally designed to be at only a fraction of yield strength when fully compressed (40% is a generic upper limit). In critical applications, they are also "preset". My guess is that mag springs are not designed as critical components and are somewhat of an afterthought.

I suspect recoil springs are also not a primary focus for most gun makers. The last sentence cited above states an idea I've been thinking about since this discussion got into full swing. Your work experience with metals and their application in the aerospace industry has been with highly specialized needs and sophisticated materials that must meet very high standards. As you say, a lot rests on the proper function of a jet engine. Recoil and mag springs that seem to be an afterthought are probably a sign of practical BUSINESS hurdles that are hard to overcome: designers in much of the firearms industry, given market size and revenues, probably don't have deep-enough pockets to find or develop better ways to get the "spring" job done.

I also suspect that most of the changes we've seen in firearm spring usage over the past 20-30 years has had more to do with how springs are USED than changes to or advances in how they are made or what they are made of.

A sacrificial spring probably wasn't "needed" until they started making very small center-fire weapons and the buying public started pushing for much smaller but still high-capacity guns. (And, it seems that a "sacrificial" spring was needed only because there was no obvious way to achieve appropriate function in the space available...) Some of the new, smaller guns were developed by small firms that simply don't have pockets deep enough to develop a new class of springs (if that is even possible.) I'd argue that Kel-Tec is emblematic of that segment of the firearms industry. But, even the bigger firms like RUGER or S&W may have a tough business case to make if they propose doing heavy R&D for spring applications.


.

HexHead
February 17, 2015, 08:16 PM
I do change my oil every 3,000 miles, cheap peace of mind.

I change magazine springs if they need it, they're cheap too.
Silly me. I follow the car manufacturer's recommendation, not the oil change marketing department's recommendation. What do those engineer's and designers know?

JohnKSa
February 18, 2015, 12:44 AM
My apologies if I came across as a pompous a-hole...not my personality at all...just let the frustration get to me.You pointed out some holes in my original experiment which is good. The new test will be more exhaustive and will have good control data for comparison.

I've got my new spring tester about 50% done and will start the test when it's ready. If everything goes well, we should have some results to discuss in 6 months or so. :D

Walt Sherrill
February 18, 2015, 10:09 AM
I'm very glad that Jlr2267 has joined the group and is contributing to the discussion. He brings a different perspective and adds to the base of knowledge here. That also means we've got at least three engineers participating from time to time, and a couple of them have more specialized knowledge of the topic. We've also had a metallurgist involved in the past.

Many of us look at OUR experience with things, and assume that our experience is typical. But those who shoot OPEN classes, compete with very hi-cap guns/mags, who carry pockets guns, or who ONLY shoots 1911s, or messes with a very small center-fire pistol (like the Rohrbaugh R9) bring a different base of experience to this type of discussion.

Re: spring replacement:

I've had to replace a few mag springs, over the years, but never in a full-sized gun that held fewer than 15-rounds. (When I was actively doing IDPA, I picked up a bunch of cheap 10-round mags and used them a lot, and they never seemed to hiccup; some of them saw a LOT of use.)

I once sold a Kahr P9 with 6-mags. I had bought it used, with those mags and two holsters. I shot it some, carried it a little, function-tested it periodically, and did so again before the sale, using 4 of the 6 mags. It seemed to function well then, and had never been a problem.

Soon after I sold it the buyers said that all 6 mags wouldn't feed properly. The buyer wanted to return the gun and get his money back. While it was a "local" FTF sale, we both still had to drive about 50 miles. The gun sale included an unused Alessi IWB holster which came with the gun when I bought it. I told the new buyer the problem was probably bad mag springs and that I would replace them at my expense, but he didn't trust the gun. He got his money back and I got the gun back. I ordered 6 new springs for the Kahr from Wolff.

When I installed the new springs I was astounded by the difference between the strength of the old and new springs. The old springs were very soft and easily flexed, but it was a CHORE to get the new springs installed, and I thought I would need a bumper jack to get them into the mag tube! More than one of the springs flew across the room several times as I mishandled the installation process. I don't know what might have happened to cause their rapid deterioration -- unless the new buyer did something to stress the springs, like stretch them because he thought they were not strong enough.

The mags were easy to load when I had the gun, but functioned properly. Once the new springs were installed the gun was 100% again -- but much harder to load. Soon after that I sold the gun and mags again (without the holster) for the price I had originally asked -- which was more than I paid for everything -- and never had a callback about feeding problems.

I later sold the Alessi holster separately for $150 on Ebay. (I woke up and did a little checking and found that Alessi holsters are much in demand and can be quite pricey.) Duh...

MICHAEL T
February 18, 2015, 11:07 AM
My Bersa Thunder is 10 years old I have use the same mag since new Its kept fully loaded and shoot about every 3 months. I ordered 2 extra mag springs when I got the pistol. Their still not used.

fletcher
February 18, 2015, 11:50 AM
If there is permanent deformation occurring, one which does in fact depend on the length of time the spring is compressed, there is *something else* going on which has not yet been explained either here, or in the academic literature.

Time for me to jump back in. Permanent deformation at room temperature by stress relaxation in springs has been addressed in academic literature since at least the 1970's. This mechanism is completely different from both fatigue and creep. You are correct that creep is not operatimg in any significant capacity at spring operating temperatures, but relaxation does occur - I have made posts in similar threads to this effect with references to papers showing effects.

One such thread. (http://www.thehighroad.org/showthread.php?p=9477681#post9477681)

In short, permanent deformation does occur in springs under constant load at room temperature. The extent of this deformation depends on alloy, stress, temperature, and time. For most good magazine springs, the effect is minimal. However, there are plenty of users reporting weakened springs which may have used less-than-optimal design or materials.

Jlr2267
February 18, 2015, 01:29 PM
Time for me to jump back in. Permanent deformation at room temperature by stress relaxation in springs has been addressed in academic literature since at least the 1970's. This mechanism is completely different from both fatigue and creep. You are correct that creep is not operatimg in any significant capacity at spring operating temperatures, but relaxation does occur - I have made posts in similar threads to this effect with references to papers showing effects.

One such thread. (http://www.thehighroad.org/showthread.php?p=9477681#post9477681)

In short, permanent deformation does occur in springs under constant load at room temperature. The extent of this deformation depends on alloy, stress, temperature, and time. For most good magazine springs, the effect is minimal. However, there are plenty of users reporting weakened springs which may have used less-than-optimal design or materials.
Thanks for taking time to share this. Your last post in the linked thread is excellent..!!

Walt Sherrill
February 18, 2015, 01:49 PM
Great contribution to the ongoing topic of interest.

(I don't know how I MISSED that earlier discussion, as that topic seems to call out to me.)

danez71
February 18, 2015, 04:02 PM
That was a great post... and was one I saw but didn't comment on because 1) I agreed and really couldn't add value & 2) he was getting past my comfort zone in terms of knowledge.

Just to be more clear... I've never needed to change a mag spring including my 21yr old BHP. But my most compact pistol is a M&P 9c. Not very compact compared to some.

My only dog in these debates is that it is doing zero good to say that all mags can be fully loaded with no I'll effects.

That's what people ask. They don't ask about creep or viscoelastic properties etc.

The right answer is " Depends on the mag... oh you have xyz?.... that's a service weapon and haven't seen reports of problems or.... oh.. you have a R9.... recoil sings are rated for about 250 rounds (was 500 btw) and there been reports of weakening mag spring"

That how we can provide meaning answers.

There are some really really smart people in this thread and I'm glad I'm here to learn from them and hopefully share some of my knowledge.

Walt Sherrill
February 18, 2015, 04:29 PM
Rohrbaugh states that the spring should be replaced every 250 cycles? Do they make any mention of how LONG you can leave a magazine loaded before replacing the spring?

I think the Rohrbaugh mag would be a perfect garage experiment to see how leaving a "sacrificial spring" loaded affects its performance.

It would be pretty lame if a Rohrbaugh could only be loaded for, say, 7 days at a time, lol. So to me, it seems like the R9 example is supporting what Jlr2267 has been saying all along. Replace after # cycles, not amount of time.It would be pretty lame if a Rohrbaugh could only be loaded for, say, 7 days at a time, lol. So to me, it seems like the R9 example is supporting what Jlr2267 has been saying all along.

I don't see the connection. Nobody mentioned Rohrbaugh mag springs, mag spring failures, or a change to Rohrbaugh-recommended mag spring usage practices. (As someone else mentioned in this discussion, single-stack mags seem to be slightly less hard on mag springs than double-stack mags.)

After the R9 service life guideline change, I talked with a couple of R9 owners who say they have gotten more than 250 rounds out of their springs -- by using these higher-count springs at the range when they practice. They also keep fresher springs in the gun when carried. No high round counts, yet, because none of them seem to want to practice a lot -- the R9 seems to be a bit like the Kel-Tec P40 in that it's not a pleasant gun to shoot.

UPDATE: I was curious about the magazine issue and downloaded the Rohrbaugh R9 Owners Manual. The recoil spring service life is 200 rounds. (I don't know whether I heard/read it wrong, earlier, or whether it's been lowered again...)

The owner's manual does not provide any guidelines for magazine usage or suggest how often the mag springs should be replaced.

danez71
February 18, 2015, 10:03 PM
^^^^^^

I'm sure I remember it was 500 and then 250. In fact, I found a thread here from back in 2013 that mentions 250.

That's got to be because the spring is getting compressed too far. It gets pretty warm in there too.


For ex: The R9 has a 5.2 OAL and the M&P9c has a 6.7 OAL. They both 'look' to have about the same amount of distance added by the short beavertail past the slide.

So roughly speaking, the slide/spring assembly is about 1.5" shorter on the R9 but they both have to open roughly the same amount to eject the shell.

Something's gotta give... and apparently its the recoil spring in the range of 200-500 rounds.

jamesinalaska
February 18, 2015, 11:16 PM
Thank you Schwing, ku4hk, and MICHAEL T.


Your responses to this question are short, direct, and memorable. And nobody can say, "Well that just isn't so."

An experiment. A magazine loaded for 20 years and still working. It answers a lot of my questions.

I like this forum because I can get good, solid answers, like yours, to good questions like the O.P.'s.

If you enjoyed reading about "How long can you keep magazine springs under tension?" here in TheHighRoad.org archive, you'll LOVE our community. Come join TheHighRoad.org today for the full version!