I have cheated on guns that my jig would not fit and used Quik Steel and a laser bore sighter to stick the scope and mounts then removed the scope and drilled and tapped, Quik Steel sets up really fast, in minutes, so it is helpfull to have another set of eyeballs when positioning the scope and mounts, plus it gives you someone to yell at if it comes out crooked, I have done 2 M N's, a 2a Enfield, a Pachamyr pivot mount on a Garand, and a homemade mount on an L1a1 this way and they all sighted in just fine. Just remember it is easier to pop off the Quik Steeled on mounts and redo, than to weld up and drill new holes.