If the SHUSH Act (H.R. 3139 and S. 1505) becomes law, firearms silencers would be classified as firearms accessories, eliminating the need for a even a background check or FFL licensee transfer. In other words, silencers could be bought and sold over the counter or mail-order just like anything else.
Since their introduction in the House and Senate on June 29th, there hasn't been much activity on the Bills. H.R. 3139, with 8 cosponsors, is in the Ways and Means and Judiciary Committees. S. 1505, with its 1 cosponsor, has been referred to the Finance Committee.
Check back or sign up for updates.