If I were standing at a gun counter today, I’d pick the 365 over the J frame for SD.
I'm almost afraid to ask, when was the last time you stood at a gun counter?If I were standing at a gun counter today, I’d pick the 365 over the J frame for SD.
He lost me too with that and I am a Mechanical Engineer. Springs fail due to cyclic stresses and a magazine sitting somewhere is not producing ANY cyclic stresses. If you keep the stresses in a spring below the Fatigue Limit it will last darned near forever. BTW, unloading and then reloading a magazine is exactly one Cycle, so doing as you suggest can actually shorten the life of a magazine spring by a few cycles.
Dear Sir, although your statement on the technical concept of "resistance of materials" is related to the cycles, as you mention compression and decompression. A material, in this case the spring of a magazine when subjected to a permanent load, is experiencing, over a period of time, a deformation of the material. Resenting its elastic property, this effect is known in mechanical engineering as "creep" and is one of the variables together with the "resistance of materials" that we Engineering Experts use when we are going to calculate a spring for a specific function . As you will understand explaining all of this exceeds the objectives of the thread topic. But you deserved a technical answer about it.
In summary, if a magazine remains compressed for a long time, its spring with ammunition fills the capacity of the magazine, it is subject to break or at least lose the adequate elasticity for correct operation.
By the way, the manufacturer calculated the spring so that this does not happen, but this does not mean that it does not happen. But sometimes it does, and it is good practice for a gunsmith to avoid leaving a full magazine for too long, as long as possible.
Thanks for your attention.
Luck !