I own a number of rifles in 257R, 6.5S, and 7x57.
There is not much difference between them, but I shot 4 deer in November with the Roberts.
I chambered that rifle in September, that is the 5th rifle in 10 years to use that reamer. That is a 26" Shilen SS select match barrel in #3 taper. My favorite barrel to build with. It finished at 24".
I am mostly shooting prone with a bipod at up to 500 yards... ~ every other year a shot out the window of the vehicle.
What does it all mean?
Smaller bore and more powder for long range.
Larger bore and less powder for short range.