Chrome silicon vs. Stainless mag springs

[ucrt]

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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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[Eric]

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.

[RAM Engineer]

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.

[MarkG]

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]

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.

[markm]

CS springs failed Magpuls corrosion tests with flying colors.

They have NO business in an AR magazine.

[TOrrock]

Thanks again guys.

[El Pistolero]

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?

[MarkG]

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.

[El Pistolero]

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.