Your first post mentions groups of 5/6cm. And did I read that right in the second post, with some of the flyers being 20/25cm apart?
Check out all of the above suggestions AND.....you're not resting it on a hard surface are you? If you are to shoot rested try it on a soft, cushioned rest. Also try freehand. Either way employ a soft, but repeatable hold and pay particular attention to trigger control and follow through. Fingers crossed this helps.....