At one time the world 200 yard bench rest small group was held with .222 using a 52 or 53 grain flat based match bullet and 4198. It would be hard to shake the logic that might point to that place as a starting point.
Frankly, I am bewildered as to the lack of accuracy you are getting from a quality triple deuce. I have owned many, from cheap single shots to SAKO Bench rest rifles, and they all shot very well with no particular fuss; basically, if the bullet made it out the end of the barrel it grouped sub MOA, at least. I have a Thompson Center single shot .222 pistol that will shoot rings around your best grouping and my old Winchester will best that. I don't believe the blitz king are at fault, exactly, but something is amiss. Try a different bullet -a Sierra Match flat base is great (one of my favorites)- and seat the bullets to recommended OAL accompanying the charge data. If you have a factory crimp die, crimp half of your rounds. Oh! And pick a starting charge and stay with it. Just shoot the rifle with that load. Lastly, I don't know what scope you are using currently but those targets you are using are far too small of me, at least. Shoot at a bullseye you can plainly center in the scope. Good luck.~Muir