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my "long term" observations of loaded magazine springs in my Mossberg 590

Discussion in 'Shotguns' started by Sheepdog1968, Oct 2, 2012.

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  1. Sheepdog1968

    Sheepdog1968 Member

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    Over a number of years, I have kept my Mossberg 590 magazine tube loaded (go to home defense gun) and I have some observations that I wanted to pass along. Please keep in mind that this wasn't a scientific study. Rather, it was me just noticing the spring every now and then and changing it out. I thought you might find it interesting.

    It is a Mossberg 590 with a 20" barrel and can hold 8 rounds in the magazine tube. And yes, I have a safe as I don't leave unattended guns loaded in the home. Ammo listed below is 2.75" 00 buck shells

    Spring 1 - original one it came with from the factory. After test firing the new weapon with a few boxes of ammo I loaded 8 rounds in the magazine and left it in the safe for one or two years. At that point I took a Loui Awerbuck class. The shotgun was working fine (never failed to deposit a shell onto the shell lifter) but the magazine tube felt week so we swaped it out. The spring was very short and the conclusion was that it must have been an incorrect short spring from the factory. Several springs later determined that wasn't likely the case.

    Spring 2 - was whatever the local range had. The spring was about 9 to 12" longer than the magazine tube (what I've been told is what you want). It worked well for the class. I went home and loaded 8 shells into the magazine tube and ordered factory Mossberg magazine spring so I would have them ready in the future if I needed them. About a year later I was going to take another shotgun class. Prior to the class I checked the magazine tube spring. It was as weak and the same length as spring 1. No biggie, I just put in the new Mossberg factory spring for the class.

    Spring 3 - the new Mossberg factory spring worked fine and provided flawless performane of the Mossberg 590. I had mentioned to the instructor what I had observed. He suggested that I store the shotgun with only 5 shells in it so the spring would be less compressed. After the class, I stored the shotgun with 5 (out of a possible 8 max capacity) in the magazine tube. About a year later, I checked the spring tension. The magazine tube spring felt weaker but maybe not quite as bad as before.

    Spring 4 - this time, I used a Wolf spring as I had heard good things about these springs. I loaded the magazine tube with 5 rounds. After 6 months or a year (my memory is foggy on when I did the install), I checked the magazine tube spring and it feels nice and strong. I plan to stick with Wolf springs for the magazine tube.

    Though some of the tubes weakened over time, they never failed on me to work. So far I'm happy with the Wolf spring (and I have another two new ones at home).

    I thought you might all find this interesting even though it isn't scientific. It's taken a while for me to "collect" this data.
     
  2. Fred Fuller

    Fred Fuller Moderator Emeritus

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  3. Sam Cade

    Sam Cade Member

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    Springs only wear through cycling, that is being compressed and released. How long a given spring stays compressed has zero effect on its lifespan.
     
  4. Sheepdog1968

    Sheepdog1968 Member

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    I had heard that as well and was a little surprised. Some of these springs didn't have many compression cycles at all on them. I should point out these shotgun springs are fairly sloppy relative to what I normally think of as a spring.
     
  5. Sam Cade

    Sam Cade Member

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    Sure. Shortening of the spring is to be expected though. When someone specs out a cheap compression spring it is common to build it slightly overlong.

    The first couple times the spring is compressed it takes a slight set and THEN it is within the intended operating range. (Good example:subcompact glock magazines.It is very hard to load them to capacity when new. People leave these loaded trying to weaken the spring when all they have to do is just mash down the follower a few times with a pen)

    FWIW, there isn't any mechanism for a compressed spring to loose strength outside of corrosion or temperature extremes high enough to destroy the entire weapon.
     
    Last edited: Oct 2, 2012
  6. 1KPerDay

    1KPerDay Member

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    I have the 590 (non A1) with the 8 round tube... the OEM spring got very weak after a while; the last round in the tube kind of dropped out, rather than being shoved out. It still worked fine in use, but I put the wolff in on the recommendation of the forum. For a while I couldn't put 8 rounds in the tube, but now I can (as long as there's a larger number of birdshot than slugs... I can't put 8 slugs in yet, at least winchesters).

    New spring seems much stronger.

    I love this shotgun, BTW.

    Here's one 3-gun stage with it just for fun :)
    http://youtu.be/tpBoezSUDzQ?t=42s
     
  7. AI&P Tactical

    AI&P Tactical Member

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    Thank you sheepdog for proving this. I post the same thing and of course I am put in my place by the "Modern Metal does not set" crowd and the "springs only weaken through using the weapon" crowd.

    I stopped debating them as I know what I know and what I know is what you found out. Great post of stating facts and not opinion by your own test.

    What is really comical is a Magazine spring for the 870 (what I use) is only $3.20 and yet some guys state they have been leaving theirs fully loaded for 20 years and they work just fine. If a man can't spend $3.20 every other year to ensure his weapon is 100% operational then he most likely does not need a defense weapon to start with.
     
  8. Dave McCracken

    Dave McCracken Moderator In Memoriam

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    I set up my first "Serious" 870 around 1980. Two shot extension, Rem spring to match. Kept 5 in it,so down one round from full. TTBOMK, I replaced that with a Wolf spring in the 90s. Still works perfectly.

    OTOH, I've had to replace a couple in hunting/GP shotguns every decade or so.

    Like AI&P said, springs are cheap....
     
  9. Drail

    Drail Member

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    There's Wolff springs and then there's OEM (whatever we can get for the cheapest price springs). If you don't know what is in your gun replace it with a quality spring. I have had an 870 for around 20 years now and the OEM spring died a quick death from leaving the magazine full for the first year. It now gets a new Wolff spring installed as soon as I can feel a difference when loading the magazine. This gun has very little range time. It has spent most of its life just sitting next to my bed. Every time someone claims that springs only wear from use and not from compression I have to laugh. It's a little more complex than that. I have talked to several police armorers who told me that about the only maintenance they ever do to their dept's 870s is replace the mag spring because it's been sitting in a cruiser rack for years and only shot once a year for qualification purposes. Eventually it gets pulled out and taken to the range only to find the last several rounds won't feed reliably. New spring and it is 100% again. I have seen this happen on my 870. Also some shells will swell up if left under compression for long periods. I have quite a few of those in a box under my bench. You gotta look at this stuff once in a while. And like AI&P says, if you can't take a shotgun, don't go. Words to live by right there.
     
    Last edited: Oct 2, 2012
  10. oneounceload

    oneounceload member

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    My 500 has the original mag spring and has been sitting fully loaded for almost thirty years. About once every two years I cycle the ammo through the gun and it works just fine
     
  11. Sam Cade

    Sam Cade Member

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    ..because anecdotes are more reliable than materials science.

    Is it?
    Tell us, how does a static spring weaken? Precisely what change takes place?

    ..and that magazine spring is being constantly subjected to vibration, compressing and releasing as the cruiser is driven. Muzzle down in a vertical mount would be the worst I bet.
     
  12. Uniquedot

    Uniquedot Member

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    This is my experience as well with my old 20" HD wingmaster.


    I doubt that question will get answered unless an metallurgist is lurking amongst us. If the spring is left compressed the atoms are still in the same position, but through release and compression (as you know) the atoms are allowed to move around as the repeated stress is allowing it. Any spring that goes bad under compression was not properly tempered when it was manufactured.
     
  13. AI&P Tactical

    AI&P Tactical Member

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    Well...... I was wrong with my 20 year comment as it is now 30 years. Let's end this tired debate before it becomes 40 years.
     
  14. Double_J

    Double_J Member

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    I had to replace the spring in my mossberg 500 after I got it. The spring still had tension and fed reliably but I noticed a LOT of rust coming off of it. I figure the original owner shot a lot of waterfowl and did not oil the spring, thus leading to rust. I bought one from wolff springs and had no further problems until it went underwater during a hurricane. I replaced the spring again and have had no problems since. That was over 7 years ago and many shells. I may replace it in the next few months when I make an order from brownells or midway. (got to pick up some other parts for a "project")
     
  15. danez71

    danez71 Member

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    Here some info that shows springs in a static compression does have a negative effect.

    Ive posted lots of data on THR and TFL.

    Oddly, people that claim that static compression has NO/ZERO impact impact on springs has ever, to my knowledge, provided any test data to support their claim.

    This 1st has data at only 200 degrees.
    http://www.spring-makers-resource.net/support-files/fig_37.pdf

    http://www.spring-makers-resource.net/spring-designs.html

    http://www.spring-makers-resource.net/compression-spring-design.html


    http://www.mechrel.com/articles/Mechanical-Spring-Failure-Modes/

    The myth is not a myth. Contant compression does affect springs.

    How much will be determined by the overall design.

    But rest assured, nothing lasts forever. Not even a spring.
     
  16. jhco

    jhco Member

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    Never had a problem leaving a shotgun mag loaded for long periods of time as far as the springs go, however, I have experienced the plastic hulls bulging a little from the applied pressure on the shells.
     
  17. JAshley73

    JAshley73 Member

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    On static-compression and spring wear...

    In my Stamping-Die class from my machinist's apprenticeship, we talked about die springs -really large, stiff springs that get 100,000's of cycles- a little bit. Indeed, cycling of springs is the largest factor of wear. However, the further you compress a spring, the more susceptible it is to fatigue and failure. And the thicker wire-diameter of the spring, the more susceptible it is to fatigue and failure. In other words, to make it last longer, make it softer, compress it less, and cycle it less.

    However, material plays a big part in this, especially when considering static wear. A properly selected spring-steel, when properly formed, heat treated and tempered, is probably almost immune to static softening under compression. But that costs money, and manufacturers have to compromise to hit a price point. I'm sure that the Wolf springs, as an aftermarket item, are a better material/process start to finish. Substitute that for cheaper steel and sub-par hardening/tempering, and the static softening would become far more likely.

    Based on most everyone's experience above, I'd say it falls exactly inline with conventional engineering expectations...
     
  18. Sam Cade

    Sam Cade Member

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    Not actually Zero, but not meaningful. In a 10,000 hour test at room temperature a .05 inch wire lost .05 of its oomph.


    Prediction of Stress Relaxation for
    Compression and Torsion Springs

    www.dtic.mil/cgi-bin/GetTRDoc?AD=ADA302507

    Prepared for
    SPACE AND MISSILE SYSTEMS CENTER
    AIR FORCE MATERIEL COMMAND
    2430 E. El Segundo Boulevard
    Los Angeles Air Force Base, CA 90245

    (coolest source ever!)
     
  19. forehire

    forehire Member

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    Another "Wolf" for wolf springs. If there is better, I have not needed to look for them.
     
  20. JohnKSa

    JohnKSa Member

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    That article doesn't say springs won't weaken from being left compressed. In fact it was about calculating how much a spring would weaken from being left compressed. It correctly assumes that they will weaken and provides a model for predicting the amount of weakening for their application which they then confirmed with experimental testing.

    For their application the figure worked out to between 2% and 3% for 1000 hours of being left compressed.

    For other applications the figures will be different based on the spring design, the spring quality and the amount the spring is compressed when under full compression per the design of the item in question that incorporates the spring.
     
  21. AI&P Tactical

    AI&P Tactical Member

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    It is comforting to know that a dumb Jarhead like me came up with the same conclusion as the Rocket Sceintist.
     
  22. Uniquedot

    Uniquedot Member

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    Maybe you're in the wrong business. :)
     
  23. Sky

    Sky Member

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    Maybe not all springs are created of equal quality.
     
  24. AI&P Tactical

    AI&P Tactical Member

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    Uniquedot - you may be right but my business is so sucessful I would be taking a serious pay cut signing on with NASA :). Besides, our all knowing and samarter then all of us (yuck) president (hopefully former president soon) has cut the heck out of the NASA buget so they are not hiring.
     
  25. danez71

    danez71 Member

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    And that 1000 hrs represents ~41 days.

    How deeply its compressed into its elasticity range has potentially more affect than number of cycles.

    If you crush the spring down... it only lasts one cycle.


    Bottom line, the number of cycles is part of the equation.Compression % in use is hugely important as is material properties.
     
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