Per my experience. Find a friendly FFL who knows about ATF6 or is willing to work with you as you get the form and fill it out for the FFL. Submit the form per instructions and wait. Talk to ATF if you have questions. Take the the ATF6, a copy of the FFL license, and a letter from the actual FFL allowing you use of the license. When you return, the ATF6 approves the gun's entry into the US, the FFL gives the gun a legit place to go, and the letter makes sure you are allowed to take it to the FFL's store. The FFL must run the gun through his books. When he signs the gun out to you, it is legally yours here in USA.

I'd be very inclined to belive a V-22 Darne would be well worth the effort.

Hope that helps.

DDA