So I'm using a PMM compensated P10C slide on my P10F frame. It runs perfectly fine with normal fire. I probably put 3-400 rounds through it without a single issue with normal target shooting. At my match on Sunday, I had two FTE's during the "double tap" on a paper target, two different stages. I didn't pay attention to what mag I was using when they happened. These are the first two FTE's I've had with the comped C upper regardless of the lower used, and being that it was while doing "double taps" I'm thinking the recoil spring should be lighter. Does anyone know what parts are compatible with the C upper? Should I just get a stainless guide rod and try a Glock 19 15# spring or something?