A common misconception is that all center-fire semi automatic rifles are restricted. This is not true. As a matter of fact the rules governing what makes a weapon restricted seem almost random. Check out the website
www.wolverinesupplies.com for more info and excellent firearms selection. Anyways you can actually own an unrestricted 50 cal in Canada or an AR180B-2 which is virtually identical to an AR-15 yet is unrestricted. A CZ 858-2 is a semi-automatic that looks just like an AK-47 (including a 30 shell banana clip that is pinned at 5) but because it is 482mm barrel instead of the standard 390mm they are unrestricted.
Handguns have some peculiar rules as well. A .25 cal and .32 cal are prohibited but .38's .40's .44 magnum's and .45's are only restricted.
Even shotguns are not immune from some strange rules. You are allowed to have a shotgun with 5 shells, but you can only bird hunt with a 3 shot shotgun.