I was wanting to set up a gun for long range hunting. 500 yards or so. I have a tekka .270 wsm a .308 norma mag and a .280. I havent shot any of them a whole lot. Which one would be better for this? What are the benefits of each? I was thinking either the .270 or .308 all though the .280 can hit the same hole with factory ammo at 100yards. What would the best scope be?