CBSA is historically known to be very unexplainable of what allows importing. So every time someone imports something or gets seized. Drop a post or a comment.

My buddy bought and crossed the US border to bring in a VFC Navy MP7 GBBR. He paid no import fees or tax and placed a chrono graph paper on the box. The agent asked if he does this as a business and he promptly said no. This was 4 months ago. So maybe it’s possible for someone else? 
-give away post (first one!?)