Alright, here's the context of my question: I have a pistol for home defense, and I keep a magazine loaded with ammunition in case I ever had to use it. Otherwise, I'd have to scuffle around and load the magazine before it could be used for its intended purpose, and that would sort of eliminate the advantage of having the pistol in the first place. I am concerned that the magazine spring, being under constant tension due to it being loaded, will have a tendency to "set" and lose elasticity. This would cause it to have insufficient pressure to push rounds into the chamber as the weapon is discharged, or initially racked. I've done quite a bit of research on gun-owner forums regarding this issue. However, answers on these forums are commonsensical, and not substantiated by physics. In most instances, answers are one of three possibilities: 1. It is cycles of tension (loading and unloading) that cause the most damage to the spring (not constant tension). So don't worry about keeping the magazine fully loaded. 2. Constant tension will cause the spring to set. As such, you should cycle your magazines every few months. 3. Cycles of tension (loading and unloading) cause the most strain on a string [due to metal fatigue], but heavy tension also causes strain. As such, you should keep your magazine loaded, but not "fully" loaded (i.e. download a few rounds). Right now, I have chosen answer "3" above as the best solution, but I'd like to know what your answer is. Here's some additional information: a. The spring is under some tension regardless of whether the magazine is loaded or unloaded. Specifically, when the magazine is disassembled for cleaning and maintenance, and the spring is taken out and allowed to expand to its full length, it is about 50% longer than it is in the magazine's unloaded state. It is compressed even further in the magazine's loaded state. (I understand that spring tension probably increases exponentially as spring length decreases linearly so that's why I elected to chose answer "3" as a compromise) b. The exact chemical composition of the spring is probably proprietary (I couldn't find it anywhere), but most sources say it is some form of steel. Here's a link to the exact spring I use in my pistol's magazine ( http://glockstore.com/pgroup_descri...?tpl=index&category_id=355&_Magazine+Springs/ ). I understand that the fundamentals of spring mechanics won't change with the material, but I figured if you had a better idea as to the chemical makeup of the spring you would probably be able to provide a more accurate answer. So, all in all, does having the magazine spring constantly under tension wear it out? And what is the best way (in regards to longevity of the magazine and reliability of the weapon to fire) to keep the ammunition loaded?