lubbockdave -
Congrats - the #1 is a classy rifle!
My Ruger M77 .257 Roberts has a 22" barrel. Federal's 120g Nosler Partition loads leave the barrel at 2682fps, although they are rated at 2780fps. Your #1 should have a 26" barrel and velocity will be closer to the 2780fps mark.
Sighted in for Maximum Point Blank Range for a 6" diameter target and assuming 2780fps:
- 1.5" Muzzle
+ 2.8" 100 yds
+ 3.0" 125 yards
+ 0.0" 233 yards
- 3.0" 273 yards
-10.0" 335 yards
My handloads push a Barnes 115g TSX to 2958fps but the extra velocity only adds another 25 yards to the -10" range (360 yards).
I have found the .257 Roberts to be a very light recoiling rifle, even with the heaviest loads, making it a real joy to shoot. Again your #1 has an advantage by being a pound heavier. Recoil for the Federal 120g load should be around 11.5 foot-pounds with a scope mounted.
Too many good choices on scopes, although your intended use will eliminate many. Is this going to be a carry rifle or a prairie dog rifle?