Keep your firearm handy for inspection by the customs guys. Theres a form you have in the States that shows you purchased that particular firearm in the States. Keep that handy. You should fill out the declaration forms ahead of time with all the required info but sign the form only in front of the agents. The form is available as a download from the above website. Coming in is usually the easy part. Going back home through your customs is often the problem. Have fun!