Ok so Im really liking Rugers new SR-762 but I wonder if just getting a big bore for my standard AR15 lower will curb my needs. I don't have a longer range rifle and wonder if something like a 6.5 or 6.8 will help fill that niche. Or is there another cal that will? I know my 5.56 will reach out to 5-600 yards but I want more "knock down" further out. What say ya'll?