I have many friends that have built their own suppressor. Many of those have built more than one. The requirements that have already been stated are what's required. I just got mine after a 65 day wait (from sent). That was the hardest part. If you decide to buy one rather than build then it's best to forget all about the whole thing after you send your packet in. You'll need a Certification of compliance with 18 U.S.C.922(g)(5)(B) regardless of whether you buy or build. All the forms that you'll need are available for order via the BATFE's website located at http://www.atf.treas.gov/dcof/index.htm
. You can order all the paperwork there. I would order more than you need simply because once you are bitten by the bug you'll need them. Before you send your forms in make copies. I sent mine with a tracking number just incase it got lost or misplaced. If I can be of any further help, feel free to contact me.