Yeah, when i first installed the 12.5 lb spring it brought back memories of failure to return to battery issues i had with an M&P years ago.
So far, in 70 rounds of live fire, it worked just fine but that is hardly a concrete test. I have no problem replacing springs often if they allow the gun to perform as i desire. However, if they're unreliable, out they go.
Ill probably have to try a wolf 13 pounder at some point as the 14 lb spring felt OK but not quite as awesome as that 12.5 lb spring. I really wish ISMI would make a 13 lb 1911 spring as i much prefer their construction/design to the wolf units.