Boiled linseed oil may not 'chemically' dry for a long time, but as far as you and I and your rifle stock are concerned, it dries to a rock hard resin that bonds with the wood fibres and actually makes it stronger.
The difference when you use BLO as a finish is that you are actually touching the surface of the wood when it is done, rather than a varnish or a shellac or polyurethene, where you are touching the coated finish on the outside.
Tung oil takes forever to dry.
