Fast twist 1-10 and faster twist in a 223 barrel are used to shoot the heavy 60 and above grain bullets . The bullet drop of the heavy bullets would be more than a 53 grain V Max at 300 yards but would be better for 600 yards shots. I do not have reloading data about the 6X45 MM round . But either rifle that shoot 1/2 inch 100 yard groups are good for 300 Yd p dog shooting. If you are only going to shoot p dogs , get an accurate 204 Ruger rifle .
