Wal-Mart's in Northern Ontario usually have a couple isles of hunting stuff; it is discounted now that the fall season is over. Wal-Mart here does sell air and paint-ball guns, plus some archery but no cartridge/muzzleloading firearms, although they do have a small ammo cabinet that is stocked with common ammunition. The storage/display/purchase/possession of firearms is heavily regulated in Canada and I think Wal-Mart just does not want the hassle.

Mike