I am assuming that by BLO you mean boiled linseed oil. Boiled linseed oil is anything but just boiled. It may be ok for gunstock finish, but I always use the unadulturated raw linseed oil for gunstock finishing, and as you indicate it is commonly used by artists as well. Raw linseed can be purchased in one-gallon size and larger, but you will usually have to order it as the local iron monger (or hardware shops) do not regularily stock it. I order mine via internet.
As some English and American gunmakers have found, using boiled linseed oil as a hot oil bath for stock bending (versus using raw linseed oil) can be a mistake. Most boiled linseed oil has chlorine in its make up as a result of the "boiling" (probably better called something else, but would not sell as well) Jack Rowe relates how one of his colleagues used boiled linseed oil for stock bend and the cholorides destroyed the finish of the action. However, this may be moot as many of the top english gunsmiths are using heat guns to heat the stocks for bending. This in itself is tricky calling for a lot of touch and feel experience of heat of walnut when it is just right. I still use hot raw linseed oil, but have a method that keeps the hot oil from soaking into to action and stock.
Just my thoughts from deep in the "bushveld"
