It doesn't really matter what they say is the reason - there is no recourse whether the decision was justified or not.
The problem is that the decisions are entirely subjective and not subject to any logic or review.
One man, the head of the SFSS of the RCMP can prohibit nearly anything he wants to, and he believes individuals should not have certain types of firearms.
The term variant is nowhere defined in law, and the act allows the RCMP (the head of the SFSS) to define variant. His definition would make you throw up, yet people have gone to jail for it.
Further, "easily converted" in also nowhere defined, nor are the directed findings of the section subject to any public scrutiny or review.
We have the twin problems of a vague criminal code and firearms act and a government that allows bureaucrats nearly unlimited discretion to make regulations and entirely subjective decisions that affect the lives of millions of people without any oversight or review.
A public service employee can decide what variant means since parliament never defined it, then decide any legally acquired firearm you own is a variant of a named prohibited firearm and not inform you. Then you can be charged with possession of a prohibited firearm. Exactly this has happened.
The politically appointed CFO is empowered to make any regulation they deem necessary for public safety, like for example requiring every range to have a safety unicorn or that your berms need to be 20 meters higher to protect the children.
Why can't you think about the children?