Cookey, I have a T3 lite 6.5x55. what made me favour the tikka was the free floating Barrel. "Patterdale Boy" has a point, Check that nothing is lodged under the barrel and check that your mod is not interfering with it(i.e. not touching). The other thing is... My friend bought a rifle recently and the scope was fitted by the shop. Turns out that when they fitted the barrel, they in advertently over tightend it and caused some damage (and erm, forgot to point this out to him). Have you or any of your friends got a barrel laser?
I also have an heym .223 and when it comes to rounds, i do not al