I've really struggled to build an accurate load using Barnes Varmint Grenades, even stoking them over hot loads of Reloder10X and VV N120 in my .223. They are incredibly fussy with seating depth and neck tension, much much worse than my usual Hornady, Sierra or Speer bullets.
I know a number of people who have also had problems with them - in fact I only know one person that succeeded, and that was with the lighter .224 VG bullet (39gn?) in a .222 with a 1:14 twist. As an alternative, the cheap Dogtown hollowpoint bullets from Midway are very good if you want a messy, frangible .22 varminting load.