Are there any exemptions from the making or transfer tax provisions of the NFA?
Yes. These are noted below, along with the required form number, if any, to apply for the exemption. Completed forms must be approved by the NFA Branch prior to the making or transfer:
(1) Tax–exempt transfer and registration of a firearm between special (occupational) taxpayers: ATF Form 3.
(2) Tax–exempt making of a firearm by a qualified manufacturer, or other than by a qualified manufacturer if the firearm is made on behalf of a Federal or State agency: ATF Form 1 and Form 2. Tax–exempt transfer and registration of the firearm on behalf of a Federal or State agency: ATF Form 5.
(3) Tax–exempt transfer and registration of an unserviceable firearm which is being transferred as a curio or ornament: ATF Form 5.
(4) Tax exempt transfer of a firearm to a lawful heir: ATF Form 5.
(5) Tax–exempt transfer by operation of law (e.g., court order).
[26 U.S.C. 5851–5853; 27 CFR 479.69, 479.70 and 479.88–91]
Source ATF: https://www.atf.gov/firearms/qa/are-there-any-exemptions-making-or-transfer-tax-provisions-nfa