I own a 22-243AI which is somewhat similar. The real advantage of these big case 22's can best be realized with the heavy bullets. I would suggest shooting the heaviest bullets that your barrel will stabilize. What twist do you have?
On the other hand, screaming bullets along at 4,600 ft/sec+ should be a blast. [img]/ubbthreads/images/graemlins/shocked.gif[/img] You can find loading data here 22-6mm data