Were to get a pellet rifle?

i am looking to buy a pellet rifle in ontario i am having a bit of a problem thoe i would like to buy a pellet rifle over 500fps but the law down here is 500fps or more u gotta register it or something so basicly my question is what store can i buy a pellet rifle over 500fps and i am over 18 years old so what will i have to do when i buy it tks