I gather it’s still possible to literally “saw off” part of the shotgun barrel ...
Shotgun barrels are typically made of steel, so it is possible to saw them off to a shorter length.
The question is: Is it legal for Canadians to do so?
The prominent Canadian firearms lawyer in the video clearly states it is not legal for an individual to do so, if the barrel is shortened below 470 mm.
Could the lawyer be wrong? Sure. Anyone can be wrong.
However, as a lawyer who dealt with this issue multiple times in the Canadian legal system, he has quite a bit of experience with it.