Herman, I have had excellant groups with SW 250 & 200 and all my testing and hunting [7/8inch to 1 inch] mostly mediuns of different kinds and deer with one boar have given excellent results but once in a while some one with a Savage 10ml has one blow usually hitting the spine or shoulder bone.
I am inclined to believe that the faster twist and higher velocity is close to the top end that they are designed for,it is also my belief that with the correct bullet placement considering the velocity and twist being used that they will give excellant results. Lee