So there is yet another post about magazine springs and whether they should be replaced, and if so, when. This is in the same theme I wrote about several years ago when there was another little flurry of articles and posts about this. I’m going to cover this ground one time for everyone.
Metal creep is caused from slippage of crystalline structures along boundary planes, whether FFC, BCC, or whatever. One reader writes that “springs don’t wear out from compression.” This is along the same lines as most of the [mistaken and incorrect] articles I linked the last time I addressed this issue that claimed that stainless steel doesn’t creep below the yield limit.
Do you know any piano tuners? I do. Yea, they have to go back a few days later and retune because of metal creep. But most piano wires are carbon steel under high stress. What about stainless steel?
Do not make the claim that stainless steel (like SS304) doesn’t suffer creep below the yield limit and at low temperatures. Yes … it … does (“In all tests at applied stress/yield strength ratios above 0.73 some plastic deformation was recorded”).
No offense, but don’t try to be an engineer if you’re not one. If you make the claim that SS304 (I presume the material of most magazine springs) doesn’t suffer from metal creep, you’d be wrong, and then you’d also be answering the question the wrong way.
The right way to look at the question is one of whether the creep is significant. It usually isn’t, and it is less significant than for carbon steel. It’s also not significant for applied stress/yield strength ratios lower than what the authors tested. Where your specific magazine spring falls in this data set is best determined by the designer, not me (I don’t have drawings or any other design information).
Besides, for most readers, you aren’t loading 34+ magazines per day and putting 1000+ rounds downrange for 300+ days per year as a workup to deployment. For 99.99% of the world, this is a pedantic question. For those who do put that many rounds downrange and have to use the magazines bequeathed to you by predecessors who did the same thing for years, you will want to watch your feed and ensure that it’s smooth, consistent and reliable. If it’s not, then change the magazine springs (or get new magazines – there could be another issue). They’re cheap, and it’s no big deal.
Note: No warranty express or implied is included with this article. Nothing here constitutes formal engineering counsel – you have to pay to get that. Nothing here includes claims on any specific magazine spring, whether said spring is loaded to the right applied stress/yield strength ratio to cause deformation, or whether anyone reading this article needs to change magazine springs in any given situation.