M&P R8 Light primer strikes
I realized that the strain screw was loose out of the factory and this should be fully tight. So I tightened the screw, which clearly added a lot of tension to the main spring and marginally increased the trigger pull tension but completely solved the FTF problem...
Aimpoint Micro H1
I put an aimpoint microH1 on top of my R8. Works very well - not as quick for target acquisition as the eotech, but still very easy to use. Only adds 3 Oz of weight.
By the way - I've been having some light primer strikes and FTFs with Remington UMC 38 specials. About 1 in 12...