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Firearms VerificationA forum community dedicated to Colt firearm owners and enthusiasts. Come join the discussion about performance, gunsmithing, troubleshooting, reviews, accessories, classifieds, and more! Colt Police Positive.38 S&W caliber revolver. Early transition Police Positive serial number 43 with New Police marking on frame. Barrel is 4'. Bore has some pits. Metal has a mostly gray patina with original.
Firearms Verification Overview  Marking Requirements Serial Number
Must be conspicuously engraved, cast or stamped (impressed) on the firearm frame or receiver
The serial number cannot duplicate the serial number appearing on any other firearm the importer previously imported
For firearms imported after January 30, 2002, the engraving, casting or stamping (impressing) of the serial number must be to a minimum depth of .003 inch and in a print size no smaller than 1/16 inch
Name of Manufacturer
Must be conspicuously engraved, cast or stamped (impressed) on the firearm frame, receiver, barrel or slide
For firearms imported after January 30, 2002, the engraving, casting or stamping (impressing) of the serial number must be to a minimum depth of .003 inch
Country of Origin
Must be conspicuously engraved, cast or stamped (impressed) on the firearm frame, receiver, barrel or slide
For firearms imported after January 30, 2002, the engraving, casting or stamping (impressing) of the country of origin must be to a minimum depth of .003 inch
Model Designation (if assigned)
Must be conspicuously engraved, cast or stamped (impressed) on the firearm frame, receiver, barrel or slide
For firearms imported after January 30, 2002, the engraving, casting or stamping (impressing) of the model designation must be to a minimum depth of .003 inch
Caliber or Guage
Must be conspicuously engraved, cast or stamped (impressed) on the firearm frame, receiver, barrel or slide
For firearms imported after January 30, 2002, the engraving, casting or stamping (impressing) of the caliber or gauge must be to a minimum depth of .003 inch

Name of Importer
Must be conspicuously engraved, cast or stamped (impressed) on the firearm frame, receiver, barrel or slide
For firearms imported after January 30, 2002, the engraving, casting or stamping (impressing) of the importer's name must be to a minimum depth of .003 inch
City & State of the Importer
Must be conspicuously engraved, cast or stamped (impressed) on the firearm frame, receiver, barrel or slide
For firearms imported after January 30, 2002, the engraving, casting or stamping (impressing) of the importer's city and state must be to a minimum depth of .003 inch
Note: The importer must ensure that these marks of identification appear on each firearm. If the manufacturer did not mark them, the importer must place the required markings on the firearm within 15 days after their release from Customs and Border Protection custody. The Director, Bureau of Alcohol, Tobacco, Firearms and Explosives may authorize other means of firearms identification upon receipt of a letter application from the importer, submitted in duplicate, showing that such other means of identification is reasonable and will not hinder the effective administration of the regulations.
 Identification of Firearms  Q: How must licensed manufacturers and licensed importers identify firearms, armor piercing ammunition? Firearms. You, as a licensed manufacturer or licensed importer of firearms, must legibly identify each firearm manufactured or imported as follows:
By engraving, casting, stamping (impressing), or otherwise conspicuously placing or causing to be engraved, cast, stamped (impressed) or placed on the frame or receiver thereof an individual serial number. The serial number must be placed in a manner not susceptible of being readily obliterated, altered, or removed, and must not duplicate any serial number placed by you on any other firearm. For firearms manufactured or imported on and after January 30, 2002, the engraving, casting, or stamping (impressing) of the serial number must be to a minimum depth of .003 inch and in a print size no smaller than 1/16 inch; and
By engraving, casting, stamping (impressing), or otherwise conspicuously placing or causing to be engraved, cast, stamped (impressed) or placed on the frame, receiver, or barrel thereof certain additional information. This information must be placed in a manner not susceptible of being readily obliterated, altered, or removed. For firearms manufactured or imported on and after January 30, 2002, the engraving, casting, or stamping (impressing) of this information must be to a minimum depth of .003 inch. The additional information includes:
The model, if such designation has been made;
The caliber or gauge:
Your name (or recognized abbreviation) and also, when applicable, the name of the foreign manufacturer;
In the case of a domestically made firearm, the city and State (or recognized abbreviation thereof) where you as the manufacturer maintain your place of business; and
In the case of an imported firearm, the name of the country in which it was manufactured and the city and State (or recognized abbreviation thereof) where you as the importer maintain your place of business. For additional requirements relating to imported firearms, see Customs regulations at 19 CFR part 134.
Firearm frames or receivers. A firearm frame or receiver that is not a component part of a complete weapon at the time it is sold, shipped, or otherwise disposed of by you must be identified as required by this section.
Special markings for semiautomatic assault weapons, effective July 5, 1995. In the case of any semiautomatic assault weapon manufactured after September 13, 1994, you must mark the frame or receiver 'RESTRICTED LAW ENFORCEMENT / GOVERNMENT USE ONLY' or, in the case of weapons manufactured for export, 'FOR EXPORT ONLY,' in a manner not susceptible of being readily obliterated, altered, or removed. For weapons manufactured or imported on and after January 30, 2002, the engraving, casting, or stamping (impressing) of the special markings prescribed in this paragraph (a)(3) must be to a minimum depth of .003 inch.
Note: Section 478.92(a)(3) Repealed on September 13, 2004
Exceptions:
Alternate means of identification. The Director may authorize other means of identification upon receipt of a letter application from you, submitted in duplicate, showing that such other identification is reasonable and will not hinder the effective administration of this part.
Destructive devices. In the case of a destructive device, the Director may authorize other means of identifying that weapon upon receipt of a letter application from you, submitted in duplicate, showing that engraving, casting, or stamping (impressing) such a weapon would be dangerous or impracticable.
Machine guns, silencers, and parts. Any part defined as a machine gun, firearm muffler, or firearm silencer in Sec. 478.11, that is not a component part of a complete weapon at the time it is sold, shipped, or otherwise disposed of by you, must be identified as required by this section. The Director may authorize other means of identification of parts defined as machine guns other than frames or receivers and parts defined as mufflers or silencers upon receipt of a letter application from you, submitted in duplicate, showing that such other identification is reasonable and will not hinder the effective administration of this part.
Measurement of height and depth of markings. The depth of all markings required by this section will be measured from the flat surface of the metal and not the peaks or ridges. The height of serial numbers required by paragraph (a)(1)(i) of this section will be measured as the distance between the latitudinal ends of the character impression bottoms (bases).
Armor piercing ammunition.
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.
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 letter 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.
Large capacity ammunition feeding devices manufactured after September 13, 1994.
Each person who manufactures or imports any large capacity ammunition feeding device manufactured after September 13, 1994, shall legibly identify each such device with a serial number. Such person may use the same serial number for all large capacity ammunition feeding devices produced.
Additionally, in the case of a domestically made large capacity ammunition feeding device, such device shall be marked with the name, city and State (or recognized abbreviation thereof) of the manufacturer;
And in the case of an imported large capacity ammunition feeding device, such device shall be marked:
With the name of the manufacturer, country of origin, and,
Effective July 5, 1995, the name, city and State (or recognized abbreviation thereof) of the importer.
Further, large capacity ammunition feeding devices manufactured after September 13, 1994, shall be marked 'RESTRICTED LAW ENFORCEMENT / GOVERNMENT USE ONLY' or, in the case of devices manufactured or imported for export, effective July 5, 1995, 'FOR EXPORT ONLY.'
All markings required by this paragraph (c) shall be cast, stamped, or engraved on the exterior of the device. In the case of a magazine, the markings shall be placed on the magazine body.
Exceptions:
Metallic links. Persons who manufacture or import metallic links for use in the assembly of belted ammunition are only required to place the identification marks prescribed in paragraph (c)(1) on this section on the containers used for the packaging of the links
Alternate means of identification. The Director may authorize other means of identifying large capacity ammunition feeding devices upon receipt of a letter application, in duplicate, from the manufacturer or importer showing that such other identification is reasonable and will not hinder the effective administration of this part
Note: Section 478.92(c) Repealed on September 13, 2004
 Q: How must firearms be identified? You, as a manufacturer, importer, or maker of a firearm, must legibly identify the firearm as follows:
By engraving, casting, stamping (impressing), or otherwise conspicuously placing or causing to be engraved, cast, stamped (impressed) or placed on the frame or receiver thereof an individual serial number. The serial number must be placed in a manner not susceptible of being readily obliterated, altered, or removed, and must not duplicate any serial number placed by you on any other firearm. For firearms manufactured, imported, or made on and after January 30, 2002, the engraving, casting, or stamping (impressing) of the serial number must be to a minimum depth of .003 inch and in a print size no smaller than 1/16 inch; and
By engraving, casting, stamping (impressing), or otherwise conspicuously placing or causing to be engraved, cast, stamped (impressed), or placed on the frame, receiver, or barrel thereof certain additional information. This information must be placed in a manner not susceptible of being readily obliterated, altered or removed. For firearms manufactured, imported, or made on and after January 30, 2002, the engraving, casting, or stamping (impressing) of this information must be to a minimum depth of .003 inch. The additional information includes:
The model, if such designation has been made;
The caliber or gauge;
Your name (or recognized abbreviation) and also, when applicable, the same of the foreign manufacturer or maker;
In the case of a domestically made firearm, the city and State (or recognized abbreviation thereof) where you as the manufacturer maintain your place of business, or where you, as the maker, made the firearm; and
In the case of an imported firearm, the name of the country in which it was manufactured and the city and State (or recognized abbreviation thereof) where you as the importer maintain your place of business. For additional requirements relating to imported firearms, see Customs regulations at 19 CFR part 134.
The depth of all markings required by this section will be measured from the flat surface of the metal and not the peaks or ridges. The height of serial numbers required by paragraph (a)(1) of this section will be measured as the distance between the latitudinal ends of the character impression bottoms (bases).
The Director may authorize other means of identification upon receipt of a letter application from you, submitted in duplicate, showing that such other identification is reasonable and will not hinder the effective administration of this part.
In the case of a destructive device, the Director may authorize other means of identifying that weapon upon receipt of a letter application from you, submitted in duplicate, showing that engraving, casting, or stamping (impressing) such a weapon would be dangerous or impracticable.
A firearm frame or receiver that is not a component part of a complete weapon at the time it is sold, shipped, or otherwise disposed of by you must be identified as required by this section.
Any part defined as a machine gun, muffler, or silencer for the purposes of this part that is not a component part of a complete firearm at the time it is sold, shipped, or otherwise disposed of by you must be identified as required by this section.
The Director may authorize other means of identification of parts defined as machine guns other than frames or receivers and parts defined as mufflers or silencers upon receipt of a letter application from you, submitted in duplicate, showing that such other identification is reasonable and will not hinder the effective administration of this part.
 ATF Rulings  ATF Ruling 2002-6 The Bureau of Alcohol, Tobacco and Firearms (ATF) has been asked by State and local law enforcement officials to trace firearms that are marked, in part, with non-Roman letters and/or non-Arabic numbers. Specifically, ATF received a request to trace a Makarov type pistol made in Bulgaria. The original manufacturer marking was ИМ 18 355. Because the importer did not stamp the firearm with a unique identifier that could be recognized by either ATF or a State or local law enforcement official, and because the marking contained a Cyrillic character, the firearm was not properly recorded, resulting in a failed trace of the weapon.
Because markings with non-Roman characters or non-Arabic are not easily recorded or transmitted through means by importers, dealers, or distributors, many firearm traces have proved unsuccessful. In some cases, an importer attempts to translate portions of the markings into Roman letters and Arabic numbers and re-marks the weapon with the serial number ДМ7639И. The importer translated the marking as LM7639i but rather than restamp the entire number merely added the letters 'L' and 'i' below the original markings. This practice often results in failed traces because those required to record the markings (importers, dealers, or distributors) may record only the translated portions or both sets of markings. Moreover, law enforcement recovering a firearm with such markings may submit a trace request lacking some portion of the markings, further impeding efforts to successfully trace the firearm.
In addition, ATF has found that some traces have failed because the required markings on the firearms barrel were wholly partially obstructed from plain view by a flash suppressor or bayonet mount, resulting in the Federal Firearms Licensee creating an inaccurate record. ATF has been unable to trace hundreds of firearms as a result of nonstandard or obscured markings.
As a result of these practices, some licensed importers my not be in compliance with the marking requirements set forth in 27 CFR 178.92[a] and 27 CFR 179.102[a] because they have marked using non-Roman letters (such as Greek or Russian letters, Δ or Д) or non-Arabic numbers (e.g., XXV).
The above regulations require markings that legibly identify each item or package and require that such markings be conspicuous. ATF has consistently taken the position that 'legibly' marked means using exclusively Roman letters, (A, a, B, b, C, c, and so forth) and ‘conspicuous' means that all required markings must be placed in such a manner as to be wholly unobstructed from plain view. These regulation apply to licensed manufacturers and licensed importers relative to firearms, armor piercing ammunition, and large capacity ammunition feeding devices, and to makers of National Firearms Act firearms.
Firearms, armor piercing ammunition and large capacity ammunition feeding devices which contain required markings or labels using non-Roman letters (such as Greek or Russian letters, Δ or Д) or non-Arabic letter (e.g., XXV), must be completely remarked or relabeled with a new serial number or other required markings that satisfy the legibility requirements described above. It is not sufficient to simply add an additional Roman letter or Arabic numeral to a nonconforming marking; a new and unique marking using Roman letters and Arabic numerals is required. When feasible, the new markings should be placed directly above the non-compliant markings.
Similarly, firearms and large capacity ammunition feeding devices which contain required markings obstructed in whole or in part from plain view must be remarked with required markings that satisfy the conspicuousness requirements described above. For example, required markings may not be placed on a portion of the barrel where the markings would be wholly or partially obstructed from view by another part of the firearm, such as a flash suppressor or bayonet mount.
In certain unavoidable circumstances owing mainly to firearms of unusual design or other limiting factor(s) which would limit the ability of the manufacturer or importer to comply with the above legibility and conspicuousness requirements, alternate means of identification may be authorized as described in 27 CFR 178.92(a)(3)(i), (ii), or (iii)[a] and 27 CFR 178.92(c)(3)(iii)[a].
Held, a Makarov type pistol imported from Bulgaria utilizing Cyrillic letters or non-Arabic numbers is not marked in accordance with 27 CFR 178.92[a] and 27 CFR 179.102[a].
Held further, an imported firearm with any part of the required marking partially or wholly obstructed from plain view is not marked in accordance with section 27 CFR 178.92[a] and 27 CFR 179.102[a].
Date signed: November 5, 2002
New provisions are under Parts 478 and 479, not 178 and 179.
Colt 38 Agent Serial Numbers ATF Ruling 75-28 The Bureau has determined that in some cases, the serial number placed on a firearm by a foreign manufacturer is adequate to provide the identification number by 27 CFR § 178.92[b]. See also 27 CFR § 178.22(a)[b].
Held, where a serial number has been placed on the frame or receiver of a firearm by a foreign manufacturer in the manner contemplated by 27 CFR § 178.92[b], and such serial number does not duplicate a number previously adopted or assigned by the import to any other firearm, the importer may adopt the serial number of the foreign manufacturer.
Provided, the importer shall in all cases place his name and address (city and state or recognized abbreviation thereof), and any other marks necessary to comply with the identification requirements of 27 CFR § 178.92[b], on such imported firearms.
New provisions are under Parts 478 and 479, not 178 and 179.
 Industry Circulars 

Name of Importer
Must be conspicuously engraved, cast or stamped (impressed) on the firearm frame, receiver, barrel or slide
For firearms imported after January 30, 2002, the engraving, casting or stamping (impressing) of the importer's name must be to a minimum depth of .003 inch
City & State of the Importer
Must be conspicuously engraved, cast or stamped (impressed) on the firearm frame, receiver, barrel or slide
For firearms imported after January 30, 2002, the engraving, casting or stamping (impressing) of the importer's city and state must be to a minimum depth of .003 inch
Note: The importer must ensure that these marks of identification appear on each firearm. If the manufacturer did not mark them, the importer must place the required markings on the firearm within 15 days after their release from Customs and Border Protection custody. The Director, Bureau of Alcohol, Tobacco, Firearms and Explosives may authorize other means of firearms identification upon receipt of a letter application from the importer, submitted in duplicate, showing that such other means of identification is reasonable and will not hinder the effective administration of the regulations.
 Identification of Firearms  Q: How must licensed manufacturers and licensed importers identify firearms, armor piercing ammunition? Firearms. You, as a licensed manufacturer or licensed importer of firearms, must legibly identify each firearm manufactured or imported as follows:
By engraving, casting, stamping (impressing), or otherwise conspicuously placing or causing to be engraved, cast, stamped (impressed) or placed on the frame or receiver thereof an individual serial number. The serial number must be placed in a manner not susceptible of being readily obliterated, altered, or removed, and must not duplicate any serial number placed by you on any other firearm. For firearms manufactured or imported on and after January 30, 2002, the engraving, casting, or stamping (impressing) of the serial number must be to a minimum depth of .003 inch and in a print size no smaller than 1/16 inch; and
By engraving, casting, stamping (impressing), or otherwise conspicuously placing or causing to be engraved, cast, stamped (impressed) or placed on the frame, receiver, or barrel thereof certain additional information. This information must be placed in a manner not susceptible of being readily obliterated, altered, or removed. For firearms manufactured or imported on and after January 30, 2002, the engraving, casting, or stamping (impressing) of this information must be to a minimum depth of .003 inch. The additional information includes:
The model, if such designation has been made;
The caliber or gauge:
Your name (or recognized abbreviation) and also, when applicable, the name of the foreign manufacturer;
In the case of a domestically made firearm, the city and State (or recognized abbreviation thereof) where you as the manufacturer maintain your place of business; and
In the case of an imported firearm, the name of the country in which it was manufactured and the city and State (or recognized abbreviation thereof) where you as the importer maintain your place of business. For additional requirements relating to imported firearms, see Customs regulations at 19 CFR part 134.
Firearm frames or receivers. A firearm frame or receiver that is not a component part of a complete weapon at the time it is sold, shipped, or otherwise disposed of by you must be identified as required by this section.
Special markings for semiautomatic assault weapons, effective July 5, 1995. In the case of any semiautomatic assault weapon manufactured after September 13, 1994, you must mark the frame or receiver 'RESTRICTED LAW ENFORCEMENT / GOVERNMENT USE ONLY' or, in the case of weapons manufactured for export, 'FOR EXPORT ONLY,' in a manner not susceptible of being readily obliterated, altered, or removed. For weapons manufactured or imported on and after January 30, 2002, the engraving, casting, or stamping (impressing) of the special markings prescribed in this paragraph (a)(3) must be to a minimum depth of .003 inch.
Note: Section 478.92(a)(3) Repealed on September 13, 2004
Exceptions:
Alternate means of identification. The Director may authorize other means of identification upon receipt of a letter application from you, submitted in duplicate, showing that such other identification is reasonable and will not hinder the effective administration of this part.
Destructive devices. In the case of a destructive device, the Director may authorize other means of identifying that weapon upon receipt of a letter application from you, submitted in duplicate, showing that engraving, casting, or stamping (impressing) such a weapon would be dangerous or impracticable.
Machine guns, silencers, and parts. Any part defined as a machine gun, firearm muffler, or firearm silencer in Sec. 478.11, that is not a component part of a complete weapon at the time it is sold, shipped, or otherwise disposed of by you, must be identified as required by this section. The Director may authorize other means of identification of parts defined as machine guns other than frames or receivers and parts defined as mufflers or silencers upon receipt of a letter application from you, submitted in duplicate, showing that such other identification is reasonable and will not hinder the effective administration of this part.
Measurement of height and depth of markings. The depth of all markings required by this section will be measured from the flat surface of the metal and not the peaks or ridges. The height of serial numbers required by paragraph (a)(1)(i) of this section will be measured as the distance between the latitudinal ends of the character impression bottoms (bases).
Armor piercing ammunition.
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.
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 letter 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.
Large capacity ammunition feeding devices manufactured after September 13, 1994.
Each person who manufactures or imports any large capacity ammunition feeding device manufactured after September 13, 1994, shall legibly identify each such device with a serial number. Such person may use the same serial number for all large capacity ammunition feeding devices produced.
Additionally, in the case of a domestically made large capacity ammunition feeding device, such device shall be marked with the name, city and State (or recognized abbreviation thereof) of the manufacturer;
And in the case of an imported large capacity ammunition feeding device, such device shall be marked:
With the name of the manufacturer, country of origin, and,
Effective July 5, 1995, the name, city and State (or recognized abbreviation thereof) of the importer.
Further, large capacity ammunition feeding devices manufactured after September 13, 1994, shall be marked 'RESTRICTED LAW ENFORCEMENT / GOVERNMENT USE ONLY' or, in the case of devices manufactured or imported for export, effective July 5, 1995, 'FOR EXPORT ONLY.'
All markings required by this paragraph (c) shall be cast, stamped, or engraved on the exterior of the device. In the case of a magazine, the markings shall be placed on the magazine body.
Exceptions:
Metallic links. Persons who manufacture or import metallic links for use in the assembly of belted ammunition are only required to place the identification marks prescribed in paragraph (c)(1) on this section on the containers used for the packaging of the links
Alternate means of identification. The Director may authorize other means of identifying large capacity ammunition feeding devices upon receipt of a letter application, in duplicate, from the manufacturer or importer showing that such other identification is reasonable and will not hinder the effective administration of this part
Note: Section 478.92(c) Repealed on September 13, 2004
 Q: How must firearms be identified? You, as a manufacturer, importer, or maker of a firearm, must legibly identify the firearm as follows:
By engraving, casting, stamping (impressing), or otherwise conspicuously placing or causing to be engraved, cast, stamped (impressed) or placed on the frame or receiver thereof an individual serial number. The serial number must be placed in a manner not susceptible of being readily obliterated, altered, or removed, and must not duplicate any serial number placed by you on any other firearm. For firearms manufactured, imported, or made on and after January 30, 2002, the engraving, casting, or stamping (impressing) of the serial number must be to a minimum depth of .003 inch and in a print size no smaller than 1/16 inch; and
By engraving, casting, stamping (impressing), or otherwise conspicuously placing or causing to be engraved, cast, stamped (impressed), or placed on the frame, receiver, or barrel thereof certain additional information. This information must be placed in a manner not susceptible of being readily obliterated, altered or removed. For firearms manufactured, imported, or made on and after January 30, 2002, the engraving, casting, or stamping (impressing) of this information must be to a minimum depth of .003 inch. The additional information includes:
The model, if such designation has been made;
The caliber or gauge;
Your name (or recognized abbreviation) and also, when applicable, the same of the foreign manufacturer or maker;
In the case of a domestically made firearm, the city and State (or recognized abbreviation thereof) where you as the manufacturer maintain your place of business, or where you, as the maker, made the firearm; and
In the case of an imported firearm, the name of the country in which it was manufactured and the city and State (or recognized abbreviation thereof) where you as the importer maintain your place of business. For additional requirements relating to imported firearms, see Customs regulations at 19 CFR part 134.
The depth of all markings required by this section will be measured from the flat surface of the metal and not the peaks or ridges. The height of serial numbers required by paragraph (a)(1) of this section will be measured as the distance between the latitudinal ends of the character impression bottoms (bases).
The Director may authorize other means of identification upon receipt of a letter application from you, submitted in duplicate, showing that such other identification is reasonable and will not hinder the effective administration of this part.
In the case of a destructive device, the Director may authorize other means of identifying that weapon upon receipt of a letter application from you, submitted in duplicate, showing that engraving, casting, or stamping (impressing) such a weapon would be dangerous or impracticable.
A firearm frame or receiver that is not a component part of a complete weapon at the time it is sold, shipped, or otherwise disposed of by you must be identified as required by this section.
Any part defined as a machine gun, muffler, or silencer for the purposes of this part that is not a component part of a complete firearm at the time it is sold, shipped, or otherwise disposed of by you must be identified as required by this section.
The Director may authorize other means of identification of parts defined as machine guns other than frames or receivers and parts defined as mufflers or silencers upon receipt of a letter application from you, submitted in duplicate, showing that such other identification is reasonable and will not hinder the effective administration of this part.
 ATF Rulings  ATF Ruling 2002-6 The Bureau of Alcohol, Tobacco and Firearms (ATF) has been asked by State and local law enforcement officials to trace firearms that are marked, in part, with non-Roman letters and/or non-Arabic numbers. Specifically, ATF received a request to trace a Makarov type pistol made in Bulgaria. The original manufacturer marking was ИМ 18 355. Because the importer did not stamp the firearm with a unique identifier that could be recognized by either ATF or a State or local law enforcement official, and because the marking contained a Cyrillic character, the firearm was not properly recorded, resulting in a failed trace of the weapon.
Because markings with non-Roman characters or non-Arabic are not easily recorded or transmitted through means by importers, dealers, or distributors, many firearm traces have proved unsuccessful. In some cases, an importer attempts to translate portions of the markings into Roman letters and Arabic numbers and re-marks the weapon with the serial number ДМ7639И. The importer translated the marking as LM7639i but rather than restamp the entire number merely added the letters 'L' and 'i' below the original markings. This practice often results in failed traces because those required to record the markings (importers, dealers, or distributors) may record only the translated portions or both sets of markings. Moreover, law enforcement recovering a firearm with such markings may submit a trace request lacking some portion of the markings, further impeding efforts to successfully trace the firearm.
In addition, ATF has found that some traces have failed because the required markings on the firearms barrel were wholly partially obstructed from plain view by a flash suppressor or bayonet mount, resulting in the Federal Firearms Licensee creating an inaccurate record. ATF has been unable to trace hundreds of firearms as a result of nonstandard or obscured markings.
As a result of these practices, some licensed importers my not be in compliance with the marking requirements set forth in 27 CFR 178.92[a] and 27 CFR 179.102[a] because they have marked using non-Roman letters (such as Greek or Russian letters, Δ or Д) or non-Arabic numbers (e.g., XXV).
The above regulations require markings that legibly identify each item or package and require that such markings be conspicuous. ATF has consistently taken the position that 'legibly' marked means using exclusively Roman letters, (A, a, B, b, C, c, and so forth) and ‘conspicuous' means that all required markings must be placed in such a manner as to be wholly unobstructed from plain view. These regulation apply to licensed manufacturers and licensed importers relative to firearms, armor piercing ammunition, and large capacity ammunition feeding devices, and to makers of National Firearms Act firearms.
Firearms, armor piercing ammunition and large capacity ammunition feeding devices which contain required markings or labels using non-Roman letters (such as Greek or Russian letters, Δ or Д) or non-Arabic letter (e.g., XXV), must be completely remarked or relabeled with a new serial number or other required markings that satisfy the legibility requirements described above. It is not sufficient to simply add an additional Roman letter or Arabic numeral to a nonconforming marking; a new and unique marking using Roman letters and Arabic numerals is required. When feasible, the new markings should be placed directly above the non-compliant markings.
Similarly, firearms and large capacity ammunition feeding devices which contain required markings obstructed in whole or in part from plain view must be remarked with required markings that satisfy the conspicuousness requirements described above. For example, required markings may not be placed on a portion of the barrel where the markings would be wholly or partially obstructed from view by another part of the firearm, such as a flash suppressor or bayonet mount.
In certain unavoidable circumstances owing mainly to firearms of unusual design or other limiting factor(s) which would limit the ability of the manufacturer or importer to comply with the above legibility and conspicuousness requirements, alternate means of identification may be authorized as described in 27 CFR 178.92(a)(3)(i), (ii), or (iii)[a] and 27 CFR 178.92(c)(3)(iii)[a].
Held, a Makarov type pistol imported from Bulgaria utilizing Cyrillic letters or non-Arabic numbers is not marked in accordance with 27 CFR 178.92[a] and 27 CFR 179.102[a].
Held further, an imported firearm with any part of the required marking partially or wholly obstructed from plain view is not marked in accordance with section 27 CFR 178.92[a] and 27 CFR 179.102[a].
Date signed: November 5, 2002
New provisions are under Parts 478 and 479, not 178 and 179.
Colt 38 Agent Serial Numbers ATF Ruling 75-28 The Bureau has determined that in some cases, the serial number placed on a firearm by a foreign manufacturer is adequate to provide the identification number by 27 CFR § 178.92[b]. See also 27 CFR § 178.22(a)[b].
Held, where a serial number has been placed on the frame or receiver of a firearm by a foreign manufacturer in the manner contemplated by 27 CFR § 178.92[b], and such serial number does not duplicate a number previously adopted or assigned by the import to any other firearm, the importer may adopt the serial number of the foreign manufacturer.
Provided, the importer shall in all cases place his name and address (city and state or recognized abbreviation thereof), and any other marks necessary to comply with the identification requirements of 27 CFR § 178.92[b], on such imported firearms.
New provisions are under Parts 478 and 479, not 178 and 179.
 Industry Circulars  
Duplication of Serial Numbers by Licensed Importers ATF has noted cases where some licensed importers have adopted the same serial number for more than one firearm. These instances of duplication have generally occurred when firearms are received from more than one source.
Title 27 CFR § 178.92[c] requires that the serial number affixed to a firearm must not duplicate the number affixed to any other firearm that you import into the United States. Those of you who import destructive devices are under the same requirement due to the inclusion of destructive devices in the definition of firearm as used in 27 CFR § 178.11[c]. ATF Ruling 75-28 also reminds you of the other identifying marks required by 27 CFR § 178.92[c]. In addition to a unique serial number, each firearm must be marked to show the model (if any); the caliber or gauge; the name of the manufacturer and importer, or recognizable abbreviations; the country of manufacture; and the city and State (or recognized abbreviations) in which your licensed premises are located.
Note: All cited references to regulation and statutes in the foregoing ATF rulings and industry circular use identifiers and section indicators in effect at the time the rulings and industry circular were approved. On January 24, 2003, ATF was part of a reorganization of government which placed it under the Department of Justice (DOJ). This transition resulted in certain changes within the numbering system and identification of ATF's regulations now issued and referenced under the authority of DOJ.
Colt Agent Serial Number Location NumberNew provisions are under Part 478, not 178.
Colt Agent Revolver Serial NumbersLast Reviewed September 22, 2016