Well.... ok here I'll explain the process as best as I can remember. its not that different from the CCW I had to do except for the CCW I had to take a test, and for the NFA Xfer I had to pay a $200 tax stamp.
First I had to wait for the can to show up before paperwork can start. Because the serial number is actually listed in the paperwork. Once that was done I had to fill out 3 papers. Get 2 finger print cards ($12 bucks I think) from the county jail. After that I had to get 2 passport photos, my friend is a photographer so it was free for me. Then I have to take the paperwork to the sheriff and have him sign off on them, which he did without hesitation. Write a check to the ATF in the form of $200 bucks, wait 5 weeks. Papers come in, pay $1300 for the can after sales tax... done. Worth it? Maybe not? Item that I had to have cuz its Tacticool, HELL YES!
You have to go through that entire process each time you buy a can. So I joked with the guys today that Im going to fillout the papers for the can for the SigP220 TB now so when its approved I'll be ready to buy the gun then too. And the papers have to stay with the can at all times, this is similar to the rules in canada, only I can shoot at night with it, I can hunt at night with it, and I can shoot it in my own backyard if I wanted too.... well not mine since I live in the city, but at my parents I could they live just outside of the city.
Hope that makes sense, ask me if you need any clarification on anything.