Alliant powders are still very difficult to find in Canada. Not impossible, but significantly more difficult than, say Hodgdon/IMR.
Pistol and shotguns powders in general are also very difficult to find currently from any brand.
Combine those two things and you will have a very bad time.
I'd recommend trying to find some Hodgdon or IMR shotgun powder instead; it'll be easier to find (but still not too easy).
I used to use Bluedot and Unique for shotgun loads. I switched to Longshot and 800x respectively because they were much easier to find (but still not that easy).
It may also help if you state a location. A 400km radius from no listed location, somewhere in Canada, wont help people give you advice if they know where a little Alliant powder is available.