I have had a bunch of people ask me what the process is for legally importing firearms into the US. I have gone through this process now a couple times over the past few years, and I think I have a good enough understanding to give you an overview. If you are interested in importing a firearm, the two things to know are that (1) it is possible to legally do this, and (2) it will be pretty expensive to do.
The customs broker I use is Polaris Worldwide Logistics. They were one of the supporters of Desert Brutality, and my import experience with them has been the best of any of the several companies I have used. I would highly recommend them if you are looking to get into this process. You can reach them via the head of their firearms department, Les Winner, at firstname.lastname@example.org.
Some resources that will be useful in this process: