Don’t know how much this helps, or if it even gets you in the ballpark. My load tool doesn’t have a listing for that bullet. Closest that I have is Hornady A-Max 208gn bullet with H4198. Max charge of 11.2gn, C.O.L. 2.260” for velocity of 1042 FPS. Max Pressure 18,800 CUP.
Nosler also has load data for a 220gr RNBT (C.O.L. 2.100”) and 220gr HPBT (C.O.L. 2.260”) H4198 Loads of 9.0 gr, 10.0 gr , and 11.0 gr. These are all good subsonic loads with the highest velocity at 1099 FPS.
Just sharing what I’ve uncovered. Have yet to load any Blackout rounds, but gathering the powders and bullets to start. I picked up Lapua Scenar L 220gr HPBT from grafs.com. Sample bullets showed them all at 220.0gr...no deviation from stated weight. It’ll be some time before I can share experiences, as I haven’t even broken in my barrel yet...just 10 rounds. Need more range time.