It's not just about the list, it's about specs like bore diameter, joules, etc like you mention. There are more firearms that will be prohib by the wording in C21 than there are on the actual list. I think the list is a bit of a distraction from the catch-all language that catches way more. .50 black powder would have to check the bore diameter limit in the bill, but I think that is covered.
The bill seems to go as far as banning pump / lever / bolt actions that hold more than 5, even with tube mags. And in the case of pump action shotguns, anything that holds more than 3x 2 & 3/4" since 1 & 1/3" shorties are readily available and it would be able to hold more than 5 of those.
And then there is the term "variants" without any definition of what a "variant" is. They are leaving that open to later interpretation from the RCMP to decide what is a variant and such decisions would be decided by a judge at the expense of whoever gets charged and wants to fight it at their expense. We could find in the years to come that all bolt actions are banned because any bolt action is a variant of some other bolt action that happens to yield more than 10000 joules, or one that can accept a shorter barrel, or one that was marketed as "tactical", etc. The vague definitions are far more reaching than the list, which is very reaching in itself. So many backdoors open for mission creep to ban virtually any firearm.
This obviously isn't about public safety, so not much point trying to rationalize whether or not someone would / could feasibly use any of these firearms effectively to harm others. If you have been watching CPAC, every time an MP asks "You say you are not banning hunting rifles, then why are these SINGLE SHOT rifles being banned?" ... Minister of Public Safety always just jumps up and does his song and dance "We're taking these assault weapons designed to kill the most amount of people in the shortest amount of time and near the anniversary of the polytechnique massacre, how dare the conservatives disregard these victims in favor of the GUN LOBBY"
There is no logic what is being banned by this bill and definitely no logic when it comes to discourse in the house.
They just snuck in a last minute amendment to Bill C11 just like they did with C21 for total internet censorship. Seems to be a new tactic to completely change the scope of the bill before the final reading.