i think that the 308 zeroed at 200 yards would shoot a little high at 75 but i would think it would still be pretty much dead on at 300 some of the other guys in here would know better i just suggested it because i know there are alot of ammo options and cheaper like i said earlier it was just something for you to look at if you were not dead set on the other 3 calibers for me it is more the availabilty and price of ammo if i want to go out and burn up a 100 rounds shooting paper during the off season