Editorial Note on Part 478
Editorial Note: Nomenclature changes to part 478 appear by T.D. ATF-411, 64 FR 17291, Apr. 9, 1999, T.D. ATF-487, 68 FR 3750, Jan. 24, 2003, and ATF-11F, 73 FR 57240, Oct. 2, 2008.

§ 478.92 Identification of firearms and armor piercing ammunition by licensed manufacturers and licensed importers. ( a ) ( 1 ) *Firearms manufactured or imported by licensees.* Except as otherwise provided in this section, licensed manufacturers and licensed importers of firearms must legibly identify each firearm they manufacture or import as follows: ( i ) *Serial number, name, place of business.* By engraving, casting, stamping (impressing), or otherwise conspicuously placing or causing to be engraved, cast, stamped (impressed) or otherwise placed on the frame or receiver thereof, an individual serial number, in a manner not susceptible of being readily obliterated, altered, or removed. The serial number must not duplicate any serial number placed by the licensee on any other firearm. The frame or receiver must also be marked with either: their name (or recognized abbreviation), and city and State (or recognized abbreviation) where they maintain their place of business; or their name (or recognized abbreviation) and the serial number beginning with their abbreviated Federal firearms license number, which is the first three and last five digits, as a prefix to the unique identification number, followed by a hyphen, *e.g.,* “12345678-[unique identification number]”; and
( ii ) *Model, caliber or gauge, foreign manufacturer, country of manufacture.* By engraving, casting, stamping (impressing), or otherwise conspicuously placing or causing to be engraved, cast, stamped (impressed) or placed on the frame or receiver, or barrel or pistol slide (if applicable) thereof, certain additional information. This information must be placed in a manner not susceptible of being readily obliterated, altered, or removed. The additional information shall include: ( A ) The model, if such designation has been made;
( B ) The caliber or gauge;
( C ) When applicable, the name of the foreign manufacturer; and
( D ) In the case of an imported firearm, the name of the country in which it was manufactured. For additional requirements relating to imported firearms, see Customs regulations at 19 CFR part 134.
( iii ) *Multi-piece frame or receiver.* In the case of a multi-piece frame or receiver, the modular subpart that is the outermost housing or structure designed to house, hold, or contain either the sear or equivalent component of a handgun, breech blocking or sealing component of a projectile weapon other than a handgun, or internal sound reduction component of a firearm muffler or firearm silencer, as the case may be, shall be the subpart of the multi-piece frame or receiver identified in accordance with this section. If more than one subpart is similarly designed to house, hold, or contain such primary component (*e.g.,* left and right halves), each of those subparts must be identified with the same serial number and associated licensee information not duplicated on any other frame or receiver. The identified subpart(s) of a complete (assembled or unassembled) multi-piece frame or receiver shall not be removed and replaced (*see* § 478.34, 18 U.S.C. 922(k), and 26 U.S.C. 5861(g) and (h)), unless— ( A ) The subpart replacement is not a firearm under 26 U.S.C. 5845;
( B ) The subpart replacement is identified by the licensed manufacturer of the original subpart with the same serial number and associated licensee information in the manner prescribed by this section; and
( C ) The original subpart is destroyed under the licensed manufacturer's control or direct supervision prior to such placement.
( iv ) *Frame or receiver, machinegun conversion part, or muffler or silencer part disposed of separately.* Each part defined as a frame or receiver or modular subpart thereof described in paragraph (a)(1)(iii) of this section, machinegun, or firearm muffler or firearm silencer that is not a component part of a complete weapon or complete muffler or silencer device at the time it is sold, shipped, or otherwise disposed of by the licensee must be identified as required by this section with an individual serial number not duplicated on any other firearm and all additional identifying information, except that the model designation and caliber or gauge may be omitted if that information is unknown at the time the part is identified.
( v ) *Size and depth of markings.* The engraving, casting, or stamping (impressing) of the serial number and additional information must be to a minimum depth of .003 inch, and the serial number and any associated license number in a print size no smaller than 1 ⁄ 16 inch. The size of the serial and license number is measured as the distance between the latitudinal ends of the character impression bottoms (bases). The depth of all markings required by this section is measured from the flat surface of the metal and not the peaks or ridges.
( vi ) *Period of time to identify firearms.* Licensed manufacturers shall identify firearms they manufacture within the period of time set forth in the following subparagraphs (A) and (B), and licensed importers must identify firearms they import within the period prescribed in § 478.112. For purposes of these subparagraphs, firearms awaiting materials, parts, or equipment repair to be completed are presumed, absent reliable evidence to the contrary, to be in the manufacturing process. ( A ) *Complete non-National Firearms Act weapons, and frames or receivers of such weapons.* Complete weapons not defined as firearms under 26 U.S.C. 5845 shall be identified not later than the seventh day following the date the entire manufacturing process has ended for the weapon, or prior to disposition, whichever is sooner. Each part, including a replacement part, defined as a frame or receiver or modular subpart thereof described in paragraph (a)(1)(iii) of this section (other than a machinegun or firearm muffler or firearm silencer) that is not a component part of a complete weapon at the time it is sold, shipped, or otherwise disposed of shall be identified not later than the seventh day following the date the entire manufacturing process has ended for the frame or receiver or modular subpart, or prior to disposition, whichever is sooner.
( B ) *Complete National Firearms Act weapons and devices, and machinegun and muffler or silencer parts.* Complete weapons defined as firearms under 26 U.S.C. 5845, and complete muffler or silencer devices, shall be identified not later than close of the next business day following the date the entire manufacturing process has ended for the weapon or device, or prior to disposition, whichever is sooner. Each part or modular subpart defined as a machinegun (*i.e.,* frame or receiver or conversion part), or firearm muffler or firearm silencer, that is not a component part of a complete weapon or complete firearm muffler or silencer device at the time it is sold, shipped, or otherwise disposed of shall be identified not later than close of the next business day following the date the entire manufacturing process has ended for the part, or prior to disposition, whichever is sooner.
( 2 ) *Privately made firearms (PMFs).* Unless previously identified by another licensee in accordance with, and except as otherwise provided by, this section, licensees must legibly and conspicuously identify each privately made firearm or “PMF” received or otherwise acquired (including from a personal collection) not later than the seventh day following the date of receipt or other acquisition, or before the date of disposition (including to a personal collection), whichever is sooner. PMFs must be identified by placing, or causing to be placed under the licensee's direct supervision, an individual serial number on the frame or receiver, which must not duplicate any serial number placed by the licensee on any other firearm. The serial number must begin with the licensee's abbreviated Federal firearms license number, which is the first three and last five digits, as a prefix to a unique identification number, followed by a hyphen, *e.g.,* “12345678-[unique identification number]”. The serial number must be placed in a manner otherwise in accordance with this section, including the requirements that the serial number be at the minimum size and depth, and not susceptible of being readily obliterated, altered, or removed. An acceptable method of identifying a PMF is by placing the serial number on a metal plate that is permanently embedded into a polymer frame or receiver, or other method approved by the Director.
( 3 ) *Meaning of marking terms.* For purposes of this section, the term “identify” means placing marks of identification, the terms “legible” and “legibly” mean that the identification markings (including a unique identification number) use exclusively Roman letters (*e.g.,* A, a, B, b, C, c) and Arabic numerals (*e.g.,* 1, 2, 3), or solely Arabic numerals, and may include a hyphen, and the terms “conspicuous” and “conspicuously” mean that the identification markings are capable of being easily seen with the naked eye during normal handling of the firearm, and are unobstructed by other markings when the complete weapon or device is assembled.
( 4 ) *Exceptions* — ( i ) *Alternate means of identification.* The Director may authorize other means of identification to identify firearms upon receipt of a letter application or prescribed form from the licensee showing that such other identification is reasonable and will not hinder the effective administration of this part.
( ii ) *Destructive devices.* In the case of a destructive device, the Director may authorize other means of identification to identify that weapon upon receipt of a letter application or prescribed form from the licensee. The application shall show that engraving, casting, or stamping (impressing) such a weapon as required by this section would be dangerous or impracticable and that the alternate means of identification proposed will not hinder the effective administration of this part.
( iii ) *Adoption of identifying markings.* Licensees may adopt existing markings previously placed on a firearm and are not required to mark a serial number or other identifying markings in accordance with this section, as follows: ( A ) *Newly manufactured firearms.* Licensed manufacturers may adopt the serial number and other identifying markings previously placed on a firearm by another licensed manufacturer provided the firearm has not been sold, shipped, or otherwise disposed of to a person other than a licensee, and the serial number adopted is not duplicated on any other firearm.
( B ) *Remanufactured or imported firearms.* Licensed manufacturers and licensed importers may adopt the serial number or other identifying markings previously placed on a firearm that otherwise meets the requirements of this section that has been sold, shipped, or otherwise disposed of to a person other than a licensee provided that, within the period and in the manner herein prescribed, the licensee legibly and conspicuously places, or causes to be placed, on the frame or receiver either: Their name (or recognized abbreviation), and city and State (or recognized abbreviation) where they maintain their place of business; or their name (or recognized abbreviation) and abbreviated Federal firearms license number, which is the first three and last five digits, individually (*i.e.,* not as a prefix to the serial number adopted) after the letters “FFL”, in the following format: “FFL12345678”. The serial number adopted must not duplicate any serial number adopted or placed on any other firearm, except that if a licensed importer receives two or more firearms with the same foreign manufacturer's serial number, the importer may adopt the serial number by adding letters or numbers to that serial number, and may include a hyphen.
( C ) *Manufacturers performing gunsmithing services.* Licensed manufacturers may adopt the serial number or other identifying markings previously placed on a firearm by another licensee provided the manufacturer is performing services for a nonlicensee as a gunsmith (as defined in § 478.11) on existing firearms not for sale or distribution.
( D ) *Privately made firearms marked by nonlicensees.* Unless previously identified by another licensee in accordance with this section, licensees may adopt a unique identification number previously placed on a privately made firearm by an unlicensed person, but not duplicated on any other firearm of the licensee, that otherwise meets the identification requirements of this section provided that, within the period and in the manner herein prescribed, the licensee legibly and conspicuously places, or causes to be placed, on the frame or receiver thereof a serial number beginning with their abbreviated Federal firearms license number, which is the first three and last five digits, followed by a hyphen, before the existing unique identification number, *e.g.,* “12345678-[unique identification number]”.
( iv ) ( A ) *Firearm muffler or silencer parts transferred between qualified manufacturers for further manufacture or to complete new devices.* Licensed manufacturers qualified under 27 CFR part 479 may transfer a part defined as a firearm muffler or firearm silencer to another qualified manufacturer without immediately identifying or registering such part provided that it is for further manufacture (*i.e.,* machining, coating, *etc.*) or manufacturing a complete muffler or silencer device. Once the new device with such part is completed, the manufacturer who completes the device shall identify, record, and register it in the manner and within the period specified in this part for a complete muffler or silencer device.
( B ) *Firearm muffler or silencer replacement parts transferred to qualified manufacturers or dealers to repair existing devices.* Licensed manufacturers qualified under part 479 may transfer a replacement part defined as a firearm muffler or firearm silencer other than a frame or receiver to a qualified manufacturer or dealer without identifying or registering such part provided that it is for repairing a complete muffler or silencer device that was previously identified, recorded, and registered in accordance with this part and part 479.
( v ) *Frames or receivers designed before August 24, 2022.* Licensed manufacturers and licensed importers may continue to identify the same component of a firearm (other than a PMF) defined as a frame or receiver as it existed before August 24, 2022 with the same information required to be marked by paragraphs (a)(1)(i) and (a)(1)(ii) of this section that were in effect prior to that date, and any rules necessary to ensure such identification shall remain effective for that purpose. Any frame or receiver with a new design manufactured after August 24, 2022 must be marked with the identifying information and within the period prescribed by this section. For purposes of this paragraph, the term “new design” means that the design of the existing frame or receiver has been functionally modified or altered, as distinguished from performing a cosmetic process that adds to or changes the decoration of the frame or receiver (*e.g.,* painting or engraving), or by adding or replacing stocks, barrels, or accessories to the frame or receiver.
( vi ) *Privately made firearms acquired before August 24, 2022.* Licensees shall identify in the manner prescribed by this section, or cause another person to so identify, each privately made firearm received or otherwise acquired (including from a personal collection) by the licensee before August 24, 2022within sixty (60) days from that date, or prior to the date of final disposition (including to a personal collection), whichever is sooner.
( b ) *Armor piercing ammunition* — ( 1 ) *Marking of ammunition.* Each licensed manufacturer or licensed importer of armor piercing ammunition shall identify such ammunition by means of painting, staining or dying the exterior of the projectile with an opaque black coloring. This coloring must completely cover the point of the projectile and at least 50 percent of that portion of the projectile which is visible when the projectile is loaded into a cartridge case.
( 2 ) *Labeling of packages.* Each licensed manufacturer or licensed importer of armor piercing ammunition shall clearly and conspicuously label each package in which armor piercing ammunition is contained, e.g., each box, carton, case, or other container. The label shall include the words “ARMOR PIERCING” in block letters at least 1 ⁄ 4 inch in height. The lettering shall be located on the exterior surface of the package which contains information concerning the caliber or gauge of the ammunition. There shall also be placed on the same surface of the package in block lettering at least 1 ⁄ 8 inch in height the words “FOR GOVERNMENTAL ENTITIES OR EXPORTATION ONLY.” The statements required by this subparagraph shall be on a contrasting background.
( c ) *Voluntary classification of firearms and armor piercing ammunition.* The Director may issue a determination (classification) to a person whether an item, including a kit, is a firearm or armor piercing ammunition as defined in this part upon receipt of a written request or form prescribed by the Director. Each such voluntary request or form submitted shall be executed under the penalties of perjury with a complete and accurate description of the item or kit, the name and address of the manufacturer or importer thereof, and a sample of such item or kit for examination. A firearm sample must include all accessories and attachments relevant to such classification as each classification is limited to the firearm in the configuration submitted. Each request for classification of a partially complete, disassembled, or nonfunctional item or kit must contain any associated templates, jigs, molds, equipment, or tools that are made available by the seller or distributor of the item or kit to the purchaser or recipient of the item or kit, and any instructions, guides, or marketing materials if they will be made available by the seller or distributor with the item or kit. Upon completion of the examination, the Director may return the sample to the person who made the request unless a determination is made that return of the sample would be or place the person in violation of law. Submissions of armor piercing ammunition with a projectile or projectile core constructed entirely from one or a combination of tungsten steel alloys, steel, iron, brass, bronze, beryllium copper, or depleted uranium must include a list of known handguns in which the ammunition may be used. Except for the classification of a specific component as the frame or receiver of a particular weapon, a determination made by the Director under this paragraph shall not be deemed by any person to be applicable to or authoritative with respect to any other sample, design, model, or configuration.
(Approved by the Office of Management and Budget under control number 1140-0050) [T.D. ATF-270, 53 FR 10496, Mar. 31, 1988, as amended by T.D. ATF-363, 60 FR 17454, Apr. 6, 1995; T.D. ATF-383, 61 FR 39321, July 29, 1996; T.D. ATF-396, 63 FR 12646, Mar. 16, 1998; T.D. ATF-461, 66 FR 40600, Aug. 3, 2001; ATF-11F, 73 FR 57241, Oct. 2, 2008; ATF 2014R-42, 84 FR 12094, Apr. 1, 2019; ATF-2021R-05F; 87 FR 24741, Apr. 26, 2022; 87 FR 51250, Aug. 22, 2022]