Hi...it isn't a jig just a very stiff, re-inforced piece of plywood. To driil the pin holes, the bbl and stock are clamped in a very accurate vise and the bbl top flat is clamped on the permanent jaw. A shim towards the muzzle levels the rifle and 2 parallel clamps hold the bbl and stock together or the RR pipe and stock at each pinhole when drilling, a pin is inserted into the driiled hole and the clamps are moved to the next pin location. Just have to slide the assembly along and all the pins are drilled w/ the same setup. Kinda crude but it's worked on many LRs....Fred