Instead of the NF rings that came with the NF-F1 I got the AI 28 MOA one piece rings. They are too thin for the dovetail on my trg, so when they are tightened instead of being directly over the action the scope is offset to one side slightly. This offset is no more than 4mm, and I can actually tell it's offset when i look through the scope. As far as I can tell, this will be a 40mm horizontal difference (if my math is right) at 1000 yards. Feel free to correct me, but is the difference worth getting a new set of rings for?
