I'd expect just about any factory load to make CDP power factor in a 3" gun. Nothing stopping you from shooting in ESP, where I'm certain any factor load would do.
230gr Hydra Shok chrono'd 850fps out of my 3.5" (195.5pf).
I shoot a 200gr polymer-coated bullet over 4.3 grains of Clays. Last time I chrono'd at a sanctioned match, my power factor from the same gun was 175+.
Of course, your ammo does not have to make power factor from your 3" gun, only from "your" 5" gun.