Compressed Mag Springs

R

Rich Lucibella

Staff
This age old question has never been answered to my satisfaction. So I pose it here.

Does keeping a mag fully loaded significantly shorten the spring life? Sound principles of physics or engineering are appreciated.
Rich
 
Rich, I hate to fall short on the first day but this answer is going to be a little shy in the physics and engineering department.

I have never had a magazine spring set on me. That isn't to say they won't, it's just never happened to me personally. I have always made it a habit to rotate my magazines at least once a month. No laws of physics involved. It's just what I do. George
 
Rich,
The only time that springs will "set" is when they are improperly heat treated or stretched past their elastic limit.
Note that the springs on your car are in a continuous state of compression, and they seldom if ever fail. When they do fail, the usual mode of failure is outright breakage, rather than sagging or taking a "set".

Other things that cause spring failure are overheating, generally in the 700+F region;
Sharp bends, holes ordeep tool marks in flexed areas; Extreme vibration; corrosion, and the like.

The only spring failures that I have seen in my own firearms over the last 30 years are due to breakage. This has never occured in a magazine, bit usually firing pin springs or
recoil springs.

Generally speaking, a well made steel spring properly designed for it's intended use should last upwards of 100K cycles.
 
There you have it guys. Kevin "Mad Dog" McClung does, in fact, exist.

Knife maker/martial artist/holster manufacturer/inventor and general all 'round Dark Genius. Some of his creations may be found in our links section.

Thanks for the reply, Mr. Dog. It should make for some lively discussion.
Rich
 
Rich- my father gave me two .45 mags that he found while going through some old uniforms and stuff. They were in the web pouch with the little snap doodad and were loaded with GI hardball. He said he wasn't sure if they had been loaded since he brought them home from WWII, but the last time he remembered seeing them was around 1950. I took them to the range last summer out of curiosity and they functioned 100% in my Commander.(I didn't try the hardball).Anyway, these had been loaded for around 50 years - the springs didn't take a set. My .02.
 
This question and doubt was brought up back in the '50's and I was assigned by Hdqrs Mar Corps to find out if 1911 magazine springs would lose their tension if stored loaded. Not to bore you with metallurgical details and all that technical crap, but my findings were that: less than two percent of the spring strength was lost over a period of four years and this would not cause loading malfunctions. I left five in a file cabinet and if some newbie hasn't broken the lock and removed them, I'll bet they will still function. That was over forty years ago.
Welcome aboard, George!! Too much time in front of a monitor will ruin your eyesight. That's why you failed the Kentucky Eyesight Test. (private joke) Doc
 
Not to doubt any of the good info presented so far..but... I must be the devil's advocate on this one, at least for a while.

Metellurgy aside, haven't we all had that Ruger MK II magazine that got easier to load as time went on? And don't make me mention Glock 10 round magazines..... That 10th round is a test of the modern hercules until a fully loaded magazine has sat around for a while and been shot and reloaded many a time.

Now, is that just me? Is it mass delusion? are we kidding ourselves about our mags getting easier to load?

so, the logically extension is that if they get easier to load over time, the springs must get weaker (or the magazine itself must be stretching.. yeah maybe that's it?) so couldn't the conceivable end result be that they get too weak to function reliably?

I too have one of those "found in the closet" WWII .45 mags that was loaded and worked fine (there were even two boxes of that old GI Hardball that worked fine after 40 years..I was young and foolish and I shot it all..), but I have percieved far too many springs as getting weaker to accept that they don't. My physics professor told me that a bowling ball and a feather should fall to the earth at the same rate.. well they don't.. unless the conditions are perfect and apparently I've had some imperfect magazines.

Seriously, I gotta go with my gut on this one, unless someone can get really convincing.

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-Essayons
 
Rob, I've noticed that magazines which are not as finely polished inside the well as they are on the outside will develop a shiney slickness from being reloaded and unloaded. Could this be the reason they are easier to load rather than a weakening of the magazine spring? It could be that the very hard spring burnishes the inside of the softer magazine sheet metal from sliding up and down and facilitates loading. I know that bolts tend to slide in and out of battery easier after a considerable number of rounds have been fired and my "45", which was match conditioned in '53 failed to return to battery when it was new but after a few matches it "wore in" and hasn't failed to go home since. The recoil spring is original and has been under tension all that time, except for cleaning. I fired "hard ball" ammo w/o a buffer so it was put through a pretty tough test for reliability. A tougher test would be in practical shooting contests. All my shooting was National Match and Marine requalification courses.
 
Rich, I knew a gunsmith who left a loaded .45 mag in his vault for 12 years, took it out and it just as strong as when he put it in.
Thats all I can put in :)


Kevin, Good to see you here! Your input is very valuble to us!

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Mouse Assassins inc.
 
Treading lightly around the retired armorer, I beg to offer a bit of additional information. It has been well established that 1911 mags AS DESIGNED, can stand being loaded for many years. There is a new problem, however, the short follower, allowing 8 rounds to be loaded in the mag.

Further, I change the recoil springs on my 1911's regularly. At about $7, I think that they are cheap insurance.

Here is what Wolff Gunsprings has to say:
http://www.gunsprings.com/1ndex.html

4. How often should I change my springs?

Wolff Gunsprings are made with the highest grade materials and workmanship. Most Wolff [recoil] springs will remain stable for many thousands of rounds. The performance of your gun is the best indicator of when a spring needs to be replaced. Factors such as increasing ejection distance, improper ejection and/or breaching, 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 that are subject to higher stress applications such as magazine springs, striker springs and recoil springs will require more frequent replacement than other less stressed springs. Most Wolff recoil springs should be capable of 3000-5000 rounds minimum before changing is required. Some recoil springs in compact pistols, especially where dual springs are replaced by a single spring may require changing after 750 - 1500 rounds. Changes in your firearm's performance are one of the best indicators that a change is needed.




5. Should I unload my magazines, rotate magazines, load with fewer than the maximum rounds? How often should I change magazine springs?

Magazine springs in semi-auto pistols are one of the most critical springs and the subject of much debate and concern. Magazines which are kept fully loaded for long periods of time, such as law enforcement applications, will generally be subject to more fatigue than the weekend shooter's magazine springs which are loaded up only when shooting. Magazine design and capacity also affect the longevity of the spring. Older designs where maximum capacity was not the goal such as the 7 round 1911 Colt magazines will last for years fully loaded. There was a lot of room for a lot of spring which reduced the overall stress on the spring. In recent hi-capacity magazines, the magazines were designed to hold more rounds with less spring material. This puts more stress on the spring and will cause 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 is not always practical. In applications where the magazine must be kept loaded, a high quality magazine spring such as Wolff extra power magazine springs, will provide maximum life. Regular shooting will verify reliability and regular replacement of magazine springs will provide the best defense against failure from weak magazine springs
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So, it seems that occasional changing of the recoil spring is accepted procedure, and leaving a 8 rd. 1911 mag fully loaded with a regular strength mag spring in it might not be a good idea.

Respectfully submitted, Walt Welch
 
Walt - excellent point on the degree of compression of the spring. Also on the cheap insurance of replacement. I know I plan on replacing my protection weapon mag springs every two years, whether they need it or not, unless someone can prove to me that they'll never fatigue.
 
Thanks Walt, very informative. I always liked a back-up but preferred a hand grenade to an extra round. I never forgot to hit the deck after throwing it, that's why I'm still here.
Wolfe Springs are excellent; never seen a bad one.
 
I have 1911 magazines that have been used for over 30 years. To top it off I keep them loaded between firings. I have never replaced a spring. I do clean them.

I have considered replacing the springs and still might but they function flawlessly.

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Better days to be,

Ed
 
Thanks Walt for your insights.

We were taught to keep one fresh magazine spring. This would be used for comparison with the used spring. You'd line the two up and if the used spring was shorter, it was replaced. The same thing was done for the recoil spring, firing pin spring, and firing pin safety block spring.
 
Interesting point, Gary. I race motorcycles, and we've found that the mainspring of the rear shock will sag a little bit (maybe 10mm) over time. It is acceptable according to the shock factories and works fine to simply bump up the preload on the spring by the amount of sag. With no preload adjustment on my magazines, I think I'll use your method to determine if springs need to be replaced.
 
I had hoped to avoid the topic of spring 'set.' You see, it depends on what your definition of 'set' is. Really. Lest there be odious comparisons of Slick Willie and yours truly, let me first point out that the word 'set' has the largest number of definitions of any word in the dictionary.

Here is what Wolff has to say re: spring 'set.': (URL: http://www.gunsprings.com/1ndex.html )
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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.

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.
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So, you see, a small amount of 'set' is normal. Every used recoil spring is shorter than a new one. As Wolff points out, this really is not cause for concern, as the ratings are adjusted for the initial 'set.'

So, how do you determine if a spring has too much 'set?' By the time this occurs, functioning will be impaired, and battering of the gun will be likely. Were I enamoured of a particular recoil spring (why, I can't imagine), I would compress it against a scale to measure the amount of force necessary to compress. I have never done this; I just toss them out, and put in a new one every 2,000 rds. or so. Likewise mag. springs. Cheap insurance.

What does anyone have to gain by seeing how long the cheapest part in your gun can last, at the expense of much more vital, and expensive parts? This doctor says use preventive medicine. Trust me, I am a doctor.

:) that one was for you, Rich :) Walt
NRA Life Member since 1972, 1911 GC shooter since 1967 (Still have it, still pristine).
 
My Colt GM purchased in 1946 for me by my Father, still uses the original magazine -- and my son shoots it on a regular basis. I used the gun for a hard ball gun when I shot bullseye.
A close friend has been in the spring business for about 45+ years, and when I worked for him a short time some years ago, I asked several questions about spring fatigue. His answer was that a properly made and tempered spring does not know if it is compressed or relaxed. GLV

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Walt,

Again you're on the mark with your sage advice. I must qualify what I wrote earlier.

The instructions given to us was for police service firearms. I suppose the lawyers of the manufacturers insist that the instructors provide this information so as to ensure that they (the manufacturer) will be less likely to be named as a co-defendant in a wrongful death lawsuit. Almost all major factory schools tell us to keep it at factory specs.

I don't doubt what you've said is true, but once we receive our marching orders, we obey (blindly like a Lacedaemonian). Otherwise, no deep pocket.
 
Just happen to remember that during the Korean grabass, they changed the standard one wire recoil spring to a twisted two wire spring in the AN-M3 20 mm aircraft cannon to gain more inertia when loading the first round by releasing the hydraulic charger. I was on the ground and can't imagine what temp the a/c were operating at, but must have been in the high minuses. I know I saw a mechanic trying to pour oil in a 6by6 and it was thick as light grease. The Navy also changed to an anti-freeze hydraulic fluid in the F9F A/C gun charging system.
I'm trying to figure out why the twisted two wire coil spring was selected. Would it be stronger or would it be faster? Scuttlebutt was that it was faster. Was the two wire spring stronger or faster in a sub-zero environment?
I just changed a hammer spring (coil) in a Stevens M 311 which measured the correct length but wasn't strong enough to bust a cap. I don't know the correct weight of the spring but do know the correct length and it was just as difficult to put back in.
I know I have switched from our original subject of slow functioning magazine springs to fast functioning hammer springs but I remember something in physics about a relationship between velocity and momentum. Is it possible for a spring to retain its' weight and still be too slow to maintain desired momentum? Would a twisted two wire coil overcome this loss of speed? I have seen this phenomenon in leaf springs in Columbia shotguns where the spring is still strong but loses its' speed apparently. Any spring experts care to comment? Isn't there a twisted two wire spring in an AK or SKS? I believe there is, but probably for design reasons, not for speed retention.
 
Twisted multiwire springs are used because they have more surface area, and are more flexible than a single wire spring of the same relative force capability.
Compare the flexibility of a 3/16" piece of cable to a rod of similar size in the same material, and you will see what I mean.
This increases their potential life span in some cases, and would be a definite plus in very low temperatures, where embrittlement can be an issue. It can also make them easier to install, and remove in cramped design spaces.
These types of springs can be found in most of the AK type weapons, several other Finnish, Swedish and Russian designs, and on many other designs used in industry.
 
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