I took my rifle with the bolt closed and dropped a bore rod in it against the bolt face and put a line on the rod with a sharpie exactly where the rod comes out of the crown. Then I took a bullet and dropped it inside of the chamber and held it in place with a dowel rod held against it and put the bore rod back in the barrel and measured it again where it came out of the crown and put another mark on the rod with a sharpie and then I measured the distance between the two lines. This gave me my OAL to the lands if that is what your wanting.