Great posts about this classic cartridge - another .257 Roberts lover here.
I tend to shoot heavy for caliber bullets in most rifles and I like the 120 Nosler Partition in my Ruger No. 1.

Seated to OAL of 2.913, this bullet will chrono 2834 M with 43.0 grains of IMR 4350 in the 26 inch Ruger tube.

I also shoot 120 Nosler BT's for practice and general shooting. Again, I rate the .257 Roberts as one of the all time classic rounds along with the .222 Remington, .270 Win, 30-06 and 45-70. My No. 1 seems to shoot nearly any decent load pretty well and very near to the same point of impact.