Here is what I think I remember reading (if I get more time later I’ll try a Google search and see if any of this is correct) about the current law on importing firearms to the US:
1. A private citizen cannot import a firearm, except certain curio and relic classified firearms manufactured before a certain date (sometime in the 1890s?)
2. Firearms can be imported by companies that have the general business and import licenses, plus special paperwork from ATF. Fees for the above are in the hundreds of thousands of dollars.
3. There are many restrictions and probations on the types of firearms that can be imported, including the probations on any weapon the Director of ATF finds to be “non-sporting, or not readily adaptable to sporting purposes.” (This may only apply to semi-autos, have to look this up.)
So to import a NS2000 someone will have to invest a ton of hours filling out forms and filing application fees, for a weapon that may be banned from importation at the desecration of a politically appointed government bureaucrat. The ban can even be made AFTER you get import approval, as it was with the Street sweeper/striker shotguns in the 70s. All this for a product of unknown market in the US.
A private citizen can, in most states, BUILD one of these for their own use, as long as they don’t sell it (don’t infringe on the international patent.) The next question, that I don’t know the answer to, can you have some of the non-firearm parts of a NS2000, like the shell and ammo feeding mechanism, shipped to your US address, so you can try to retrofit American made barrels, trigger groups, mag tubes, etc?
