Nice rifle, .222 is a good caliber for your posted needs.
thoughts are :
Did you "throw" the powder charge or weigh /trickle each charge? (either is fine as long as the method is consistent, personally I throw my charges)
try some differing bullets Manufacturer such as speer TnT, Noslers, even Sierria's in the 40gr that are flat based, and shorter in length than the V-max's are. They usually shoot tighter than a BT inside the 500ish yard line.
Better optic probably would tighten the existing load up. maybe.
But I wouldn't throw out that load looks to be a winner, varmint nor paper cares about a es or sd variation only gun writers do.