Okay, so I have rebuilt four of my older mags with Wolff 30rd extra power springs.  I also ordered an "ESpring" titanium 30rd replacement spring from Oly Arms.  

The claim is that the ESpring can remain loaded for years without taking any kind of set.  I am also aware (from this website) that the real wear and tear on a mag spring is cycling it up and down.  Not from (necessarily) keeping it loaded.

My question is, at $19 a pop, is the ESpring really worth it?  Has anyone else used one?  I just want the BEST for my mags.

Kevin-

Thanks for the well thought out reply.  You make a really good point about value.  I certainly could get more with Wolff Springs.  

HELL,THE TAPCO SPRINGS ARE AS GOOD AS THEY GET,I HAVE REPLACED ABOUT 15 SPRINGS WITH THEM,NEVER KNEW I WAS SO CLOSE TO FTF WITH THE OLD SPRINGS,THE TAPCO IS LIKE A 15% POWER SPRING,THEY ARE (NOT) OVER LENGTH,TAKE A REGULAR USGI SPRING,PUT THEM SIDE BY SIDE,AND RUNG F/RUNG,(SAME SIZE,AND THE WAY THE MAG WORKS AFTER THAT,WAS GREAT)..I EVEN HAD A 40 THAT HAD A CHEAP SPRING IN IT,I REPLACED IT WITH A TAPCO,THIS STEEL MAG(WHICH I DON'T CARE FOR,EVEN THE ENGLAND MAGS)TURNED OUT GREAT,I POLISHED THE FEED LIPS WITH THE OLE DREMEL TOOL,AND THIS BABY IS A-1...CHEAP TOO..BUT I WOULDN'T BUY ANYMORE,GOT THEM FOR $6EA AT A GUN SHOW,3-40's,3-30's,now with just some new springs,and followers,they work great..might even last longer than a usgi???

P.S.WITH A LULU LOADER/UNLOADER,YOU CAN UNLOAD THOSE MAGS,AND LOAD THEM IN NO TIME,JUST LEAVE 1 LOADED FOR THOSE UNEXPECTED TIMES,WHICH WE HOPE NEVER COME...

Kula223-

I did not know that Tapco made replacement AR mags.  It is always good to have choices.

I think Kevin hit the proverbial "nail on the head" with his point that I could buy several Wolff mags (plus some other stuff) for the price of one ESpring.  I just like the idea of always leaving several mags loaded (SHTF scenario - whatever).  My thought was to use the ESpring mags, with the idea that they would still work in 40 years when my grandchildren want to use them.  But at the same time, I could simply load up on Wolff springs, and replace them every 10 years or so (if that is even necessary).

I wonder if anyone at Wolff has ever done any tests on their AR 30rd mag springs to see how long they can remain loaded before they begin to take any sort of set.  I know that the up/down motion is what really wears out a spring, but I cannot believe that leaving a spring under tension for a couple of years does not eventually cause it to take a set....