75's have the trajectory of a 45/70...not condusive to a one shot one kill in 223 velocity...range estimation is critical.
Rifles that are twisted for 75's have longer throats also. Longer throats = shorter barrel life for the lighter bullets. You can only jump bullets so far before accuracy starts fading.
Of course, if you are a steel plate shooter, you have a lot more lee way in the accuracy department.
