With the .222 it's almost harder to find a powder that doesn't work rather than one that does
REACH has made it a bit trickier as H335 and H4198 both worked really well for me in the past, I would look at Ramshot Xterminator or Reloader 7, both give good velocity and, more importantly, great accuracy.
I have reloaded for 3 .222s and around the 20gn mark of RL7 with a good 50 or 52gn bullet, all three have shot under 1/2" at 100, typically .3 - .4" edge to edge.