I have used HCR to accurize many rifles as well as bought rifles from them. They are top notch class acts.
As stated they will not touch the kimbers as they are inconsistent. Kimber makes a fine pistol but the long guns can be good and bad, depends on what you get.
far as 300 wsm my HILL CO rifles Harvester is a .45 gun all day long with factory 180gr loads, my McWhorter is a .15/.20 all day long with factory 165 and 180 grain loads. My savage 300wsm is half inch all day long with wincherser powermax 180 grain factory loads.............
with a Kimber you will be lucky to get a 3/4 group. it needs to be bedded, have the crown checked, have the trigger adjusted, but most of all you will have to handload to get that rifle to find a load it likes.
Good Luck because 300wsm is one fine caliber and you will love it!
Life is Short; Live, love, Hunt
270 Winchester.......Jack had it right