The ATF Form 20 is used to get permission to transport an NFA firearm from the state where it is registered to another. It is used for both permanent and temporary relocation. You must submit it for approval by the NFA Branch of the ATF prior to transporting NFA firearms either way, except for the temporary relocation of a silencer.
What are NFA firearms? Machine guns, silencers, short barrel rifles, short barrel shotguns, destructive devices and “any other weapons” which is a category of firearms. Remember, they must all be registered lawfully in the first state, and you must be able to possess them in the second state, or you may be in violation of the law.
What is temporary relocation of a silencer? Well, we have been told six months or more… but we are checking with NFA Branch on this. You may want to submit one anyway to be cautious.
When used for temporary relocation, a Form 20 states the travel dates. If you go past the end date… the instructions say that you will need a NEW Form 20 to be allowed to transport your firearm back home!
You can find the ATF Form 20 here: https://www.atf.gov/forms/download/atf-f-5320-20.pdf
How long does approval take? NFA Branch advises us that you must permit at least 30-45 days for consideration… the more time the better. Given that the same Examiners who approve the transfer of newly purchased or inherited NFA Firearms must review the Form 20, you should allow 60 days or more in our opinion just to be on the safe side. Their workload is extreme, so apply early or you may have to leave your NFA firearm behind.