Short answer, yes it is a problem, you'll need a rifle or shotgun with a barrel that's a bit longer than 18".
You can't hunt with restricted or prohibited firearms in Canada. Some handguns are prohibited, and any that aren't prohibited are restricted. That alone eliminates the possibility of hunting with any handgun in Canada.
Restricted firearms also include long guns with an OAL less than ~26" or a barrel less than ~18.5". I don't remember the metric measurements off the top of my head, but an 18" barrel is too short.