As a non resident, it is next to impossible to get a handgun legally into Canada. Unless you are a professional shooter going to a sanctioned national match I really don't think you have a prayer of them letting you in with it.

The triplicate form is a firearms deceleration. You will need that if you are bringing any firearm into Canada, as well as pay the fee (I believe it is $25 Canadian).

Seriously....do not try to bring a handgun into or through Canada. No good will come of it. There is simply no way to make it happen legally.