View Full Version : Chrome silicon vs. Stainless mag springs
I realize that I should probably know this already, but what are the advantages/disadvantages of either chrome silicon magazine springs vs. stainless magazine springs in M16 magazines?
Thanks.
Chrome silicon has better fatigue life. Regular stainless costs less.
You could make springs from coat hangers as long as you were diligent about replacing them often enough.
Chrome silicon has better fatigue life. Regular stainless costs less.
You could make springs from coat hangers as long as you were diligent about replacing them often enough.
Thanks, that reflects my gut instinct.
"You could make springs from coat hangers as long as you were diligent about replacing them often enough." - No you can't, the yield strength is not high enough to survive one loading.
CS can last longer, SS is more corrosion resistant.
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I've disassembled and gone through a few hundred used mags the past year and have never seen more than a surface rust, no pitting or rust through. Just a little rust that you could basically just scrape off with your thumbnail. Maybe I just haven't seen a bad one yet??
I'm sure if the CS spring was exposed to salt water, they'd rust more ... but I haven't seen it.
Magpul, Brownell's, and NHMTG use SS springs in their current mags. It looks like the new USGI mags all have SS Springs. A new mil-spec?
It depends on what grade SS they use, but some grades of SS will rust like crazy if exposed to salt water?
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Like SS, not all CS springs are the same. Some CS are coated to help prevent rust, but this is one untreated on pulled from the wrapper.
http://img.photobucket.com/albums/v503/AR15forme/USGI%20Mag%20Disassembly/IMG_6085.jpg
RAM Engineer
02-06-11, 06:03
I'd be willing to bet that most mags would have issues with feed lips LONG before they got to the number of cycles where CS vs SS makes any difference.
Maximum stress levels occur at the surface of the spring. Surface defects (rust / corrosion) can seriously reduce a spring’s fatigue life. I would be inclined to choose a stainless spring over a chrome silicon version.
Suwannee Tim
02-06-11, 07:48
Maximum stress levels occur at the surface of the spring. Surface defects (rust / corrosion) can seriously reduce a spring’s fatigue life. I would be inclined to choose a stainless spring over a chrome silicon version.
Mk18 is correct about maximum stresses occurring at the surface of the spring and defects exacerbating fatigue. There are three modes of spring failure, breakage, fatigue and creep. Fatigue is a consequence of many, hundreds at least, usually thousands or more loading / unloading cycles and the result is fracture. Creep occurs with continuous high stress and the result is a relaxation of stress resulting in a loss of spring force. I have looked and can't find documentation of my recollection that chrome silicon steel is creep resistant but fatigue prone.
El Pistolero
02-06-11, 07:51
This may be a dumb question but how can I tell what kind of springs I have in my magazines? I have several different types of mags and of the ones I've taken apart most have the dull copper-colored spring in them. Is dull copper chrome silicon? Or SS?
CS springs failed Magpuls corrosion tests with flying colors.
They have NO business in an AR magazine.
This may be a dumb question but how can I tell what kind of springs I have in my magazines? I have several different types of mags and of the ones I've taken apart most have the dull copper-colored spring in them. Is dull copper chrome silicon? Or SS?
Sounds like stainless. 302 stainless with a wire diameter of 0.055 is the most common.
Suwannee Tim
02-06-11, 08:55
...have the dull copper-colored spring in them. Is dull copper chrome silicon? Or SS?
The silicon steel transformer core laminae I have seen have all been dull copper colored which I think is characteristic of silicon steel but I do not know this for sure. Stainless is always whitish silver. Corrosion is a major issue with silicon steel but since it is easily inspected I would not consider it a fatal flaw. Creep in a spring is easily detected, the spring gets shorter, this may happen with a magazine that is kept loaded for a long time. Fatigue is a consequence of loading and unloading and is not easily detected.
Not sure, but I believe CS springs claim to fame is valve springs and similar applications, due to fatigue resistance. Fatigue usually does not become a problem in magazine applications. I have never seen a broken magazine spring.
It is actually stress relaxation that occurs in magazine springs, not creep, although the phenomena are closely related. A loaded magazine spring experiences constant displacement and an ever diminishing load. Creep occurs when the load is constant and the material stretches until failure.
Suwannee Tim
02-06-11, 12:06
I stand corrected on creep versus relaxation. If you want a spring made and call Associated Spring or some other, they are likely to only have the diameter wire you want in a couple of materials and stainless will be one of them the other being music wire or CS. Often things get made out of a specific alloy because the alloy was on hand. I once made a widget out of inconel because I had a suitable piece of metal. The widget proved useful and more were ordered and made of inconel. The machinist had a hard time finding material and it was expensive but it had to be inconel....because inconel got written into the specs. Sheesh!
I stand corrected on creep versus relaxation. If you want a spring made and call Associated Spring or some other, they are likely to only have the diameter wire you want in a couple of materials and stainless will be one of them the other being music wire or CS. Often things get made out of a specific alloy because the alloy was on hand. I once made a widget out of inconel because I had a suitable piece of metal. The widget proved useful and more were ordered and made of inconel. The machinist had a hard time finding material and it was expensive but it had to be inconel....because inconel got written into the specs. Sheesh!
We use a LOT of Inconel where I work. Fun stuff.
Suwannee Tim
02-06-11, 16:36
It didn't need to be inconel. Plain carbon steel would have been fine. But they didn't want to change the process so inconel it was!:haha: Show me an engineer who is afraid to change his process and I'll show you an incompetent fool who does not understand and is not in control of his process.
El Pistolero
02-06-11, 18:52
Sounds like stainless. 302 stainless with a wire diameter of 0.055 is the most common.
Stainless has the dull copper color? I always assumed the copper color was surface rust/oxidation so I thought they might be chrome silicon, as some of my mags also have gray springs and my understanding was that SS doesn't corrode like CS.
Suwannee Tim
02-06-11, 20:53
Stainless has the dull copper color? I always assumed the copper color was surface rust/oxidation so I thought they might be chrome silicon, as some of my mags also have gray springs and my understanding was that SS doesn't corrode like CS.
No, CS is copper color and stainless never is, at least that is my informed speculation. CS is not corrosion resistant like stainless.
El Pistolero
02-06-11, 20:55
No, CS is copper color and stainless never is, at least that is my informed speculation. CS is not corrosion resistant like stainless.
Ok that's what I thought. Copper color = chrome silicon, gray = stainless.
By the way, has anyone ever used the CMMG braided springs?: http://cmmginc.secure-mall.com/item/CMMG-Braided-Wire-Replacement-Spring-915
I used them before and wasn't impressed, they don't fit more than 28 rounds in a mag, even after cutting 3 coils off the spring. I ditched them and put USGI springs back in my mags (glad I only bought 3 to test). Just curious if anyone else had the same experience.
Ok that's what I thought. Copper color = chrome silicon, gray = stainless.
Not necessarily. I've seen some USIG that have a slight goldish tint to them and CS that are gray to black.
By the way, has anyone ever used the CMMG braided springs. Tried in conjunction with their SS followers and removed them shortly thereafter. The spring is installed up-side-down, which was odd. The combo was not smooth and seemed to scrape along the inside of the tube.
These (http://www.44mag.com/product/stainless_steel_ar15_magazine_spring/ar15_magazine_components) KICKASS.
I've been using them for quite a while. They're cheap and they're 10% stronger. Swapped all of my 30rd/20rd mags out with these. Keep lots of pressure on the bolt catch.
mkmckinley
02-08-11, 22:00
These (http://www.44mag.com/product/stainless_steel_ar15_magazine_spring/ar15_magazine_components) KICKASS.
I've been using them for quite a while. They're cheap and they're 10% stronger. Swapped all of my 30rd/20rd mags out with these. Keep lots of pressure on the bolt catch.
Sounds good. What have you put'em through?
Sounds good. What have you put'em through?
Well, I only have been using them for a little over a year now, but they've held up 100% while being loaded/stored full. They've held up 100% through many range trips (maybe 400-500rds per mag x 5-6 mags?) I've got them in a total of 35-40 mags, but only the 5-6 get heavy range time.
Hardly a long enough time to judge accurately, but they're going just as strong as day one. I really like the added pressure - feels more like 20% more power.
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