If you can't shoot your rifle's ammo into groups under 1/3 inch all the time at 100 yards with metered powder charges holding a 3/10ths grain spread, forget the powder charge. Go find what's broken, or at least bent way out of shape on the performance curve, then fix that. That powder charge parameter is just fine.
US Navy Distinguished Marksman Badge 153
Former USA Palma Team Member
NRA High Power Long Range High Master
NRA Smallbore Prone Master