Do Orlite or Thermamold magazine springs hold up any better than USGI mags?  Trying to see if these mag springs will take staying loaded for say up to couple weeks at a time and still have reliable feedings.

Thanks

metal springs don't fatigue under normal loading. You can leave them loaded forever and not worry about the springs.

Plastics can "creep" if left under a constant load, on the other hand. Their material properties are different than those of metals.

I dunno if the stress of a loaded magazine is sufficient to cause creep in Orlites or Thermolds. I've had a thermold loaded up in a closet for a year or two; I'll try to take it out this weekend and see if it shoots.

Orlite mags are more britle and prone to cracking but both mags can stay loaded for a long time.  I prefer Thermolds and have 2 that've been loaded for 2+ years, there was a third but I tried it at approx. 18 months and it functioned perfectly.  I'll try another one on my next shooting trip and let the third sit for awhile.