I had owned a Kimber of Oregon 89 BGR in 280 Remington that was beautiful, but would only shoot 1/2" moa groups with bullets jammed into the rifling, and loaded way down to 7x57 levels, so I traded it for a Kimber Montana in 300 WSM. That rifle shot well, but only after a lot of work finding a bullet it liked ~ Hornady 165 IB, and W760.
That said in 2009 I sent it off to Shilen, and put a #4 Select Match Grade Ratchet 4 groove in 6.5/300 WSM. Sure it shoots little groups, but that's after a new barrel, stock work for the barrel profile being slightly heavier, although looks like a Kimber barrel profile, and trigger work by Kimber.