With groups like that, I'd first investigate the scope. Yes, I know everyone says that, but, if you check closely, you might find something. I've had loose mounts, rings and objective lenses bouncing off of the barrel chamber.
Secondly, I've had more than I'd like to admit problems post-bedding where the action was not tightened down enough. Pillars have addressed some of this, but, prior to doing that, I'll buy some allen head action screws that can be torqued down sufficiently. Has seemed to add almost more to accuracy than the bedding job. Go figure.
