I have run red dot in my .40 with a 180 fp. It cycled well but I have not done any serious accuracy testing with it.
The 2002 alliant reloading guide shows a max of 5 grains with 180 jhp
I have tried both 4.1 and 4.5 with 180 hi-tek coated both cycled my XDM 3.8 and 5.25