I have the above referred gun and it shoots terrible groups. I'm shooting Winchester Supreme 55 Grain ballistic Silvertips. The scope is a Leupold VXIIc 4x12x40. I'm shooting out of a vise at 100yds. Getting 2" groups which are unacceptable by me. I should of bought another Tikka. Any help would be greatly appreciated. Heavier bullet maybe 95 Grain?