I have been following this thread and appreciate all the info you share on the M&P platform. I have been waiting to see how durable the Delta point is when mounted on the slide. Do you know if anyone has developed a comp. for the M&P since you started your build.
I shoot 147's at about 130PF with a 13# recoil spring. I have run it that way for a few years and just recently put in a reduced power striker spring with no problems. But I do use federal primers.
Our lives intersect with the lives of others for a reason. Sometimes it is hard to know if you are there to help them or if they are helping you. It sounds as if a bit of both are going on in this situation.