dem4570,
You didn't mention the condition of the bore.Check the scope base/rings and make sure that they aretight. Did you use loctite onthe base screws,how old is your powder.
What kind of groups were you getting vertical/horizontal or all over the dang place.
If you know your powder is good, I'd try different projectiles 1st. Cayugad has this same rifle and the loads he gave are excellant loads to try.
This is your 1st post.....Welcome