Their use of proprietary powders allow them to get max performance that the handloader can't do, so if the pressure is within Handi capabilities, factory ammo would be the only choice.
As far as 3000fps 150gr loads, the Federal Fusion does well over 3000fps in my SS.30-06 Handi, so there's no gain there for a Handi, the short action bolt rifle would benefit tho.
Tim