as far as i know (and i'm a newb) it is illegal to sell gun replicas in canada. don't know why it just is. and its illegal to sell gas projectile guns that shoot over 500 feet per second and they have some other regulations to, like age and so on. Even guns that aren't replicas but kinda look like real guns can sometimes be seized by canada customs out of ignorance.
i've gathered all this info from this site. (many different threads)
i just wish that there were stores in canada that could contact ksc and other manufacturers to buy parts for you that aren't restricted by canada customs. i'm finding it very hard to find specific parts for my guns.