I used to use straight boiled linseed oil but began using Tru-Oil gunstock finish and use it on all of my bows now. It is easy to apply, easy to repair if needed and if you don't like the glossy finish I use a quick spray of satin poly over the Tru-Oil to cut the shine.
The problem with just linseed oil is you constantly have to add more and more coats. Once the bow is finished with Tru-Oil(which is a linseed oil finish) it is good for many years. If you ever need to refinish or repair the bow, Tru-Oil it works well by just feathering the repair and adding more over it.