CMP land and grove count don't matter just get a quality barrel and have a good gunsmith put it on, I have had the following barrels on my 300wm Schneider 6 land and a Schneider 5P, Hart 6 land, Mike Rock 5R, Obermeyer 5R a Lilja 3 land, Kreiger 4 land and lastly a Pac-Nor Poly they only one...