If you run anything but the factory weight springs you will have a problem sooner or later.
You cannot compare spring rate between 1911/2011's to M&P's, they are two completely different guns. 1911's do not have a spring in the back trying to pull the gun out of battery (striker spring) so you have to run a heavier spring in M&P's
You all are welcome to keep trying, but when it fails on a stage in a major, you just lost to the guy that runs the stock springs.
lastly there is no such thing as cycling faster, if a gun cycles it cycles, heavier spring slide goes back slower but returns faster, lighter spring slide goes back faster but returns slower. Now they will cause the sight to track differently, but that doesn't really matter either so long as the sight is returning consistently.
Thanks Dan I really apperciate your help the stock spring is 16.5lbs , I'm finding out that some are reducing the power of the striker spring and that sounds to me like asking for a problem for sure.. the recoil srpings are the same on both the .40 and the 9mm right? That is intersesting I would like the gun to track alittle bit flatter I'll hit the weight room before I lighten all the springs I guess anyone ever try a 15lb ismi on a captured rod maybe?