i dont know what a custom KS mountain version is. but i got a model 700 ADL and I love it. tis in teh .270 caliber, shoots good, easy to clean and gets er done. if i were to have had a choice in teh gun again, i would have opted for a stainless version, so i wouldnt worry about rust as much. but the REM model 700's are good guns to go with IMO