Below is off the ATF website
https://www.atf.gov/file/82791/download
Gunsmithing Date approved: December 27, 2010
A dealer is “engaged in the business” of gunsmithing, as defined in 18 U.S.C. 921(a)(21)(D) and 27 CFR
478.11, when he/she receives firearms (frames, receivers, or otherwise) provided by a customer for the
purpose of repairing, modifying, embellishing, refurbishing, or installing parts in or on those
firearms. Once the work is completed, the gunsmith returns the firearms, and charges the customer for
labor and parts. As with an individual customer, a licensed dealer-gunsmith may receive firearms
(properly identified with a serial number and other information required by 27 CFR 478.92) and conduct
gunsmithing services for a customer who is a licensed importer or manufacturer. A dealer-gunsmith is
not “engaged in the business” of manufacturing firearms because the firearms being produced are not
owned by the dealer-gunsmith, and he/she does not sell or distribute the firearms manufactured. Once the
work is completed, the dealer-gunsmith returns the firearms to the importer or manufacturer upon
completion of the manufacturing processes, and does not sell or distribute them to any person outside the
manufacturing process. Under these circumstances, the licensed dealer-gunsmith is not “engaged in the
business” of manufacturing firearms requiring a manufacturer’s license.
In contrast, a dealer-gunsmith may make or acquire his/her own firearms, and repair, modify, embellish,
refurbish, or install parts in or on those firearms. If the dealer-gunsmith then sells or distributes those
firearms for livelihood and profit, the dealer-gunsmith is engaged in his/her own business of
manufacturing firearms. A person engaged in the business of manufacturing firearms for sale or
distribution is required to be licensed as a manufacturer, identify/mark all firearms manufactured,
maintain permanent records of manufacture, submit annual manufacturing reports, and pay any taxes
imposed on firearm manufacturers. A licensed dealer-gunsmith who becomes licensed as a manufacturer
must also segregate all firearms manufactured for that business separately from firearms for which
gunsmithing services are being performed.
To facilitate inspection and ensure that ATF can determine that a licensed dealer-gunsmith is not engaged
in the business of manufacturing firearms for his own sale or distribution without a manufacturer’s
license, licensees may take the following steps:
(1) maintain a copy of the current, active license of all contracted licensees;
(2) maintain a copy of the contract and all instructions for gunsmithing services rendered;
(3) maintain a copy of the invoices for gunsmithing services;
(4) timely and accurately reflect all firearms acquisitions and dispositions consistent with the contract
for gunsmithing services rendered; and
(5) in the case of a licensed dealer-gunsmith, maintain required bound acquisition and disposition
records for all gunsmithing activities separate from other dealer’s records.
Unless licensees take these steps, ATF may presume that a particular dealer-gunsmith is engaged in his
own business of manufacturing firearms for sale or distribution without a manufacturer’s license, and take
corrective administrative or other enforcement action.