I put rubber washers between the forearm and the barrel to get the Triumph to group tighter.
It sounds like maybe you had some heavy oil in the barrel and did not clean it out good before starting to shoot. I tuned up a Revolution for one of the guys in our club and it is an excellent rifle; it ended up able to hold 3/4 of an inch. It has the potential of being as popular as the Omega and the Triumph or more so. I hope the new Knight co. brings it back with a few improvements to balance and locking mechanism.