Do a search under sabotloader's posts. He made a detailed thread showing how to accurize the Omega. I sanded the barrel channel with a dowel rod wrapped in sandpaper and used BJ weld to strengthen the stock between the lugs. Passes the dollar bill test and shoots 1" groups with the right load.

If yours passes the dollar bill test, you secured the barreled action to the stock with the gun pointing up, and you are certain your scope and mount are in perfect order, then perhaps you just need to work on finding the right load for your gun.