I fitted an Anshutz rail in my laminated stock. I had a friend with a mill do the cutting. He had a sharp bit the same width as the rail. We laid out the depth and length of cut and made a slow cut. The fit was perfect, there was no ripping out of any wood. The stock had not yet been finished. There were only two problems, one is that the wood of the stock LOOKED straight but was not, so the mill cut was slightly deeper in some parts and slightly less in others. The mill was accurate but the wood was not. Second was when finishing, the finish material added slightly to the walls of the cut necessitating some careful sanding of the edges of the cut to fit in the rail. IMHO, chisel cutting for a rail on a laminated stock would be difficult and prone to damaging the edges of the cut.
Roger
Roger