You have to apply for a permit to bring a firearm into canada.
http://www.cfc-ccaf.gc.ca/online-en_ligne/form-assistance/indiv_forms/909_e.asp You can do it when you land. If you get it ahead of time you can have it filled out and it will save some time. I think it costs $50 us. If you get it soon enough you can send it off and get a portion of your money back. Though, I doubt that you have enough time to do this now. Expect to spend a considerable amount of time at immigration because they will do a back ground check on you for the permit. What I'm saying is don't schedule yourself to tight. Hope this helps.