Re: Looking for setup tips - inlet for forearm rail
I once built a jig out of plywood that located a guide slot along the bottom of the stock. The jig was tricky since the stock doesn't have square cross section. I started with a piece of plywood about as long as the barrel channel. I cut triangular shaped wooden pieces ~ 4 inch wide that would support a similar piece of plywood under the forestock. They were triangular because the forestock I was working with was thinner at the front than the back. The reason the triangular pieces are so wide is to provide a wide, square to the top of the stock, bearing surface for the plywood under the forestock. When screwed together this arrangement clamps the forestock tightly in a wooden box. Remove the box from the stock and ut a guide slot in the plywood under the forestock to fit the appropriate router guide bushing. Screw it all together making certain the guide slot is centered and located where you want it lengthwise. After all that work, which will make you wish for a friend with a milling machine, cut the accessory slot with the router.
For guns like shotguns with forestocks that are disconnected from the buttstock and where the width of the forestock doesn't vary you can use a router table and just set the fence at the right distance from the center of the forestock. If the forestock does vary in width you can attach a tapered guide to the fence.
