Its likley a combo of things barring everythings tight and ready to go(scopes good and tightened down and everythings clean and no barrel pittign). Get a few diff boxes of ammo in diff manufacturers and bullet weight/types and practice. The mix of the two should leave you more satisfied not only with the guns performance but yours as well.

If that does not solve the problem you could always have a smith look at it and see if there is a hidden underlying problem.