It really is very simple in that if two cartridges use the same case,and the same design pressure,the cartridge with the larger bore will drive the same weight of bullet at a greater velocity.Another example would be the 270win and 30-06 with 150gr bullets.The 30-06 has a larger bore so it will drive the 150gr bullet faster despite the better ballistic co-efficient of the 270 bullet.However as the range increases,the higher ballistic coefficient of the smaller diameter bullet will result in it maintaining it's velocity longer and closing the gap on the larger diameter bullet.I would als be very leary of the barnes manuals as many reloaders have foundthem to contain a fair amount of questionable data.