Kimber makes a sweet rifle. I really like mine in .223 Rem.I have two rifles chambered to the .257 Bob. A Ruger #1B that has so far only had Norma 100 gr. loads through it and a Winchester M70 Featherweight that is so far a decent shooter but needs more load work. So far I've only run 100 g. Sierra Pro-Hunters and the the 100 gr. Barnes TSX through it Groups run in the 1.25" range so far with 44.5 gr. of IMR-4350. I use that load for both bullets. CAUTION: max load. Start at least 2.0 full gr. below that level and work up.
On that .257 Bob Norma ammo, it's been discontinued for a long time now. When I bought the Ruger #1B, 5 boxes of that ammo came with the gun. It was good stuff and an accurate load but it's no more.
I haven't shot any game with the rifles yet. I'd planned on trying it out on deer this year but I didn't draw a tag.