The sequence goes like this:
Register for the 4 day handgun course.
Receive confirmation of your enrolment.
Request the BATF form 6 and fill out all the info on it. Include your written confirmation of your registration. This process can be done by email or snail mail or fax. Two of us that went from Thunder Bay faxed the forms in together.
This form 6 requires that you enter the make, model, country of manufacturer, your underwear size (kidding there...). I stated the make, Norinco, model "two tone sport" 1911 45 ACP. Made in China.
Batf had no problem with me bringing the Norc into the US, so long as I made sure I took it back out with me. I never brought any ammo. I stated that I would purchase the ammo at the institute and it would all be expended there. Made things a lot easier.
Next you will need a special ATT to go through an international airport with your handgun. This is easy to obtain. A phone call to the Chief Provincial Firearms Officer, followed by a fax of your written confirmation of attendance at the course, copy of your BATF form 6, approved by the batf, and you're good to go. This additional ATT is good for one year. At the suggestion of the CPFO, I had several international airports added to this ATT. My original club ATT remains unchanged.
I carried a copy of all my paperwork on my person, all the time. Extra copies were carried in my range bag, suitcase, and in the lockable steel case I used to transport the pistol in my luggage. (Must be in checked luggage).
My experience in airports in both US and Canada customs was better than excellent. I identified that I had a handgun in my luggage, and that I had all the appropriate documentation right here in my hand. After all the bells and whistles went off, (kidding again...) the clerk went and found someone who knew what to do. I went off to a separate room where the customs folks wanted to see if the gun matched the documentation. (logical) Most of the conversation revolved around the four day shoot I was going to and what a blast it was going to be. I had the same experience in both Canadian and US customs. I kinda think the US customs guys just wanted to fondle a Norinco.
My advice is if you make a conscious effort to make the customs officer's job easier for him/her, the probability of having a smooth journey through customs increases dramatically.
I carried all that documentation around with me the whole time I was on US soil. The only time I ever needed it was at airport customs.
Would I go again? Hell yeah. They took this old senior from never drawing from a holster to drawing from concealed and putting two in the thoracic cavity in .9 secs. with a box stock norinco. I know you young bucks are probably a lot faster than that, but they sure taught this old dog a lot of new tricks in four days.
edit.. I'm not that smart to figure all this procedure on my own. The good friend I went with from Thunder Bay had been to Front Sight twice already and walked me through the process. If anyone has any questions about the process itself, I'd be happy to answer them. I'll check back a little more often.