GemTech offered their interpretation of legal requirements for supressors on their web site.  If I may paraphrase, one cannot borrow, lend, buy, sell, or transport subject item across state boundary without "blah, blah,  $$$$, ATF, blah blah".

Their interpretation did not say mere "possession" required approval.  Is it correct to assume that mere "possession of subject object" does not require "blah, blah $$$, ATF, blah,blah", any state requirements withstanding?

So you have to have BATF approval to take a suppressed weapon across state lines?