Hornady manual states starting at 17.4gr of IMR4198 with the 55gr VMAX, with a max load of 20.0gr at 2.25" COL. Test gun used was a rem700, I've got no experience with this specific powder, I hope this helps.
19.6/19.7 imr4198 seems to be the common load COL 2.25. As always, never start that close to max. For what it's worth, 27.5 CFE 223 are amazing with the 55 Vmax.