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February 27, 2011, 04:11 AM | #1 |
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Mag spring integrity - loaded vs. unloaded
I'm new in the semi auto handgun of defense use . What is the thought of leaving a mag loaded for a long period of time vs loading it just prior for use to carry ? While the spring is under compression for a long period of time, would the spring lose any of its integrity. Thanks for your input
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February 27, 2011, 07:21 AM | #2 |
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A PROPERLY made mag spring will not 'take a set'. I've never replaced a mag spring and never worry about leaving a magazine full.
BTW always number your magazines so if there is a functioning problem you can differentiate between the mags.
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February 27, 2011, 08:18 AM | #3 |
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Do you put blocks under your vehicle's frame to unload the springs when you're not using it? Of course not! Springs working within their elestic limits are not damaged by being loaded or by repetitive motion (as long as heat is allowed to dissipate). Magazine springs don't move fast enough to heat up.
By the way, welcome to The Firing Line!
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February 27, 2011, 08:57 AM | #4 |
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These gentleman are correct. Magazine springs can wear out, but generally only after years and years of use. You may run into issues on "economy" weapons or cheap aftermarket examples however.
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February 27, 2011, 09:16 AM | #5 |
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This discussion pops up about every month here on the firing line. I've got a little document I paste in when I see the question asked.
A lot of people will tell you their experiences -- which will generally be based on one type of gun and magazine, and make generalizations based on that experience. Those are good experiences, but they may not be typical. Guys who shoot 1911s, for example, almost never have to replace mag springs. Folks in the states with 10-round limits on mags, seldom change mag springs for many of their guns. But folks who shoot high-capacity race guns in competition, may change them a lot. Last year I sold a Kahr P9 with eight mags, mags I had gotten from the original user. The mag springs simply died, almost overnight -- the gun just wouldn't feed. It had worked fine a few weeks before i sold it, the last time I shot it. The buyer returned the gun, got his money back. He didn't trust the gun. I bought new springs, and the gun was suddenly running 100% again, and I later sold it for more. The springs in Kahr P9 mags are stiff, and they're hard to install. They have to do a lot to push 7 and 8 rounds in such a small gun. The prior owner must have left some of them fully loaded -- I never did. There are springs and there are springs. It depends on how they were designed, and what they were intended to do. Someone cited car springs. While I never put my car up on blocks, I've had suspension springs (both coil and leaf) that had to be replaced -- they DO wear out. But I don't think I've ever heard of tappet springs (the ones that are used with intake and exhaust valves) having to be replaced except as part of a major overhaul.) Here's a link to a in-depth discussion of the topic here on The Firing Line. Be sure to read all the way to the end. One of the participants is a mechanical engineer who did a bit of research on the topic, and cited a number of sources. This seems to be the best presentation I've seen, and the most technically complete and correct. It's based on a good bit research and isn't based on one shooters limited experience with his or her guns. The author of the most informative parts is a member here who goes by the name Bernieb90. I think it's response #41. The question was about "stretching springs" to rejuvenate them, but the discussion led to a much wider exploration. http://thefiringline.com/forums/show...ht=spring+life Put simply -- if a mag spring is pushed to it's design limits, spring life can be shortened. For many gun springs and mag springs, leavings mags fully loaded simply won't make a difference. But, for the mag springs in 16-18 round 9mm mags, hi-cap mags in .40s and .45s, or springs for some of the sub-compact guns, keeping them fully loaded CAN make a difference. Recoil springs in some of the subcompact 1911s and other small guns have to be replaced far more frequently than recoil springs in full size guns. Many of the newest guns use springs in ways that they weren't used in years past, and springs are now a disposable/renewable resource -- something that wasn't the case in the old days. Rotating mags doesn't prolong spring life -- it simply spreads the wear. Springs don't heal from non-use. They don't deteriorate if they're not overstressed. Stretching springs may cause them to fail, although one participants in the discussion swears that is NOT the case. I've seen this deterioration in a number of guns and mags I've owned and used. I've got other mags (a bunch of 10 rounders for IDPA competition, and 7-rounders, back when I messed with 1911s) that I'm sure will never fail, being of good steel from reputable sources-- and never being overstressed. (My CZ mags, for example, use the same springs in both the 10-round versions and 16-round versions. The mag tubes are physically similar, but in the high cap version, that "same" spring must do a lot more work and be compressed a lot farther. Any wonder that hi-cap mags might wear out a bit more quickly?) Check the Wolff Springs FAQ area, too. Last edited by Walt Sherrill; February 27, 2011 at 09:24 AM. |
February 27, 2011, 12:27 PM | #6 |
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Good info Walt.
I have no idea why people think that ONLY cycling will wear a spring and that stress and time does not not matter. |
February 27, 2011, 04:13 PM | #7 |
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Springs are designed for certain amounts of stress. They don't get tired, and they don't heal. They can't tell time, either.
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February 27, 2011, 05:01 PM | #8 |
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Stress over time does cause relaxation/load loss/creep.
If designed properly, it will not impact the function. Ex: http://www.spring-makers-resource.ne...les/fig_37.pdf Read post 41 in Walts post/reference thread Also: http://www.spring-makers-resource.ne...ng-design.html http://www.spring-makers-resource.ne...g-designs.html http://www.spring-makers-resource.ne...ce_summary.pdf And http://en.wikipedia.org/wiki/Elasticity_(physics)) http://en.wikipedia.org/wiki/Plasticity_(physics)) http://en.wikipedia.org/wiki/Viscoelasticity http://en.wikipedia.org/wiki/Creep_(deformation)) Just a snippet: Taken from http://en.wikipedia.org/wiki/Viscoelasticity "All materials exhibit some viscoelastic response. In common metals such as steel or aluminum, as well as in quartz, at room temperature and at small strain, the behavior does not deviate much from linear elasticity. Synthetic polymers, wood, and human tissue as well as metals at high temperature display significant viscoelastic effects. In some applications, even a small viscoelastic response can be significant. To be complete, an analysis or design involving such materials must incorporate their viscoelastic behavior. Knowledge of the viscoelastic response of a material is based on measurement" Its really not a question if.... its a question of will it impact the function. Properly designed, not really a concern. Last edited by danez71; February 27, 2011 at 08:53 PM. Reason: fixed links |
February 27, 2011, 06:18 PM | #9 |
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Your links aren't working. (Looks as though you need to do them again, to get the proper FULL URL.)
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February 27, 2011, 08:28 PM | #10 |
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Thank you Walt. Links fixed in above post.
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February 27, 2011, 08:36 PM | #11 |
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Wow! I'm really impressed. When you know what to look for (and how to decide whether you've found the right stuff), you can find marvelous stuff on the internet.
Thanks. The Moderators ought to make this message chain a STICKY, somewhere. |
February 27, 2011, 09:57 PM | #12 |
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As I have said hundreds of times-
Properly made, designed, and maintained springs don't wear out, unless they are stressed past their elastic limits. Car leaf springs are the same as any other. If you overload them, they will take a "set." |
February 28, 2011, 08:46 AM | #13 | |
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Quote:
By the way, nice post Walt.
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February 28, 2011, 10:27 AM | #14 |
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You need to buy a different car!
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February 28, 2011, 10:53 AM | #15 | |
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Quote:
The only automotive coil springs I've changed were on 20+ year old pickups. I've seen broken leaf springs, but they were the result of loaded trailers on rough roads.
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February 28, 2011, 04:11 PM | #16 |
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Gunnotes-
Ever thought there might have been something else wrong with that gun? 3 or 4 springs failing at the same time tells me the springs were cheap aftermarket items that were not properly made. And, if the springs were the problem, the gun should have worked fine once you replaced them. |
February 28, 2011, 06:58 PM | #17 | |
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Quote:
Don't tell us about your 50+ years of collecting, shooting, and hunting experience -- we've heard that before. Give us, instead, an explanation based on more than anecdotal evidence (your experience). If there is a connection, I'm sure others here will be able to repeat your experiences and confirm your claims fairly quickly. I'm curious, too, how many times you've had to replace the mainspring in a BHP or 1911 that has been carried cocked-and-locked for long periods. I continue to be amazed that your personal experience and knowledge is always superior to people who make their livings dealing with the materials and processes being discussed -- and who offer pretty credible evidence, from respected/respectable sources for their claims and counter-claims. Amazed, but not surprised. Last edited by Walt Sherrill; February 28, 2011 at 07:39 PM. |
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February 28, 2011, 07:23 PM | #18 |
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Thanks Walt for that post
Gunnotes just what I expected you are about to pop my spring Barry |
February 28, 2011, 08:27 PM | #19 | ||||
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Quote:
Quote:
Quote:
Quote:
Who's definition of "properly designed" are we using? Our desires or the designers practical limitations? Creep/sag/viscoelastic deformation.... call it what want. The fact is: "All materials exhibit some viscoelastic response. In common metals such as steel or aluminum, as well as in quartz, at room temperature and at small strain, the behavior does not deviate much from linear elasticity. Synthetic polymers, wood, and human tissue as well as metals at high temperature display significant viscoelastic effects. In some applications, even a small viscoelastic response can be significant. To be complete, an analysis or design involving such materials must incorporate their viscoelastic behavior. Knowledge of the viscoelastic response of a material is based on measurement" Until someone posts some actual sverifiable evidence to the contrary.... there isnt any logical reason to doubt science. The more the sping is compressed, the faster it wears. It is not a pass or fail issue that once it goes past a certain point it fails. As capacity increases in the same size mag or same capacity with a smaller mag, spring durability suffers. |
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February 28, 2011, 09:11 PM | #20 |
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gunnotes - I share Walt's incredulity. Please explain in detail how the power factor of a cartridge affects magazine springs.
[Added] We won't wait for an answer to the question - gunnotes has left the building. |
February 28, 2011, 10:50 PM | #21 |
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I apologize for the discontinuity in this thread, a number of posts are now missing because they were posted by a multiply registered troll.
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March 1, 2011, 07:16 AM | #22 |
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Troll, huh? Interesting.
At least he elicited some pretty good responses from some others here who are quite knowledgeable in the subjects being discussed. Some of that was info we might NOT have gotten, otherwise. I think the question of mag spring performance has been pretty-well explored and explained by folks (not me) who brought a bit of knowledge to the table. (I got one private message from one of those knowledgeable participants that was very informative; since he didn't post it publicly, I didn't share it -- but it was very good information.) The troll was one of the more subtle trolls I've seen. It took a pretty savvy moderator to catch it. But, he may NOT have left the building; he may be hiding in the attic with our crazy uncle... |
March 1, 2011, 08:06 AM | #23 | ||
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Quote:
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Proud member of the NRA and Texas State Rifle Association. Registered and active voter. Last edited by Sport45; March 1, 2011 at 08:29 AM. |
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March 1, 2011, 08:41 AM | #24 |
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Cycling of the spring causes fatigue. No two ways about it.
Keeping the spring in any other state other than its natural position causes viscoelastic deformation. How much and how long is the million doallr question. Just read the 1st link and the wiki links I posted above. The other links are good too but just start with those please. ALL MATERIALS exhibit viscoelastic deformation. |
March 1, 2011, 09:49 AM | #25 | ||
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So how is it the valve springs in a '83 pickup truck with 150,000 miles can still meet tolerance for height and compression? That's after being compressed for 25 years and cycling to near-stack some 135 million times? (I put them back in.)
Quote:
For brevity, I left out the however part. But how can you "agree in loose terms" with this and believe the same thing said with different words is wrong on so many levels? All in the same post? A paper clip is a good example. You can bend it back and forth until it breaks. That's fatigue failure. Have you ever seen a paper clip break from normal use? Keep in mind this thread is about magazine springs. And I'm jumping to the conclusion that quality magazine makers select springs that aren't stressed past their elastic limit when the magazine is fully charged and pressed against the bottom of a slide.
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