There is a place in Vernon called Guns & Archery. It is located near the brewery. I can't recall the street name, but it is in the bottom floor of a 2 story building (it looks quite run-down). Across the street is a vet clinic.
alternatively, if you are looking for outdoor stuff in general, there is the Vernon Outdoor Store.
http://www.members.shaw.ca/vernonoutdoorstore/