FWIW, Based upon my quite limited knowledge of Canadian Firearms Law, I believe that it's not so much that they are not permitted to possess & own Firearms, but rather their Regulations are very 'model specific', so to speak. IIRC, an example may be found in the many of Ruger's popular Handgun Models. For example, many of their Models are specifically manufactured with not 4.0" but rather 4.2" Barrels, in an effort to comply with Canadian Firearms Laws, which consider a 4.0" Barrel to be an 'Restricted Short Barreled Weapon', requiring a Special License & Documentation. I also know an advanced Collector of Japanese Nambu Pistols & related items, & she had to specially register most of her Collection due to their having barrel lengths of 'just' under the mandated length. In fact, & I can't confirm this as fact without rechecking my Notes, but IIRC, she had to have many the under length examples 'De-Watted', & or rendered inoperable. ( Which to me, as a long time collector of Japanese Nambu's is nothing short of an Cardinal Sin !! ) So basically, Canadian's may own Firearms, & from what I understand a great many do. However, most tend to be so lack of a better word, an 'less aggressive' design. As in, bolt action, slide / pump action, single shots are popular, & so forth. Until not all that long ago, semiautomatic .22 Longuns were allowed, but IIRC, they too were disallowed due to some high profile shooting in which one was used. That's in a nutshell, what I know of Canada's Firearms Laws, FWIW.
Best, Dom P.