An airsoft gun that mimics a real firearm with near precision, and shoots a projectile capable of causing serious bodily harm is not considered a replica. If it does not cause serious bodily harm it is considered a replica. The CBSA considers this to be 366 FPS with a 0.20g round, that is strictly for importation. It is for legal classification however, otherwise the minute an airsoft gun breaks down it would technically become an illegal replica. So that is the airsoft/airgun classification though for legal use and ownership. However, ANYdevice resembling a real firearm with near precision is a replica for legal terms of firearms legislation and the criminal code, and is considered prohibited in Canada period. That's ownership, transport, making it, import, etc.
States each have their own gun laws, like a 3mm orange tip, etc. But not only will you not be able to bring it back, that may get you arrested. You also may get arrested before going down.
You did a good job of making it, but it looks like you did a little too good of a job. Sorry dude.
ďREALITY IS LIKE A STONE. TO MANY ITíS HARD AND COLD, THEY CANíT HUG IT OR EAT IT, IT ONLY FRUSTERATES THEM AND DOESNíT DO THEM MUCH GOOD. TO OTHERS ITíS STRONG AND DEPENDABLE, YOU CAN BUILD WITH IT, BUILD UPON IT, OR WORK WITH IT, ALSO USE IT TO SMASH PEOPLE IN THE FACE.Ē