This is one of those questions that gets asked over and over again and I should have written about it long before now.
But today I correct that omission.
Let’s walk through this in 10 easy steps.
1) When you build an NFA item subsequent to a Form 1 approval, you are legally the ‘manufacturer’ of the resulting NFA item even if it is built upon an existing serialized lower.
2) 27 CFR 478.92 and 27 CFR 479.102 both lay out the requirements for placing identifying markings on items you ‘manufacture’.
3) These regulations require that you engrave a serial number, model (if applicable), caliber or gauge, manufacturer’s name, and the city and state where the item was ‘manufactured’.
4) If you are using an NFA trust to hold your NFA items then the trust name is the manufacturer’s name you will need to engrave. If not, you will need to engrave your full legal name as the manufacturer.
5) When you ‘manufacture’ an SBR or SBS using an existing lower the ATF allows you to ‘adopt’ the serial number, caliber/gauge, and/or model already identified on the lower if the lower meets or exceeds the marking requirements. See ATF Ruling 2013-3 embedded below.
6) The marking may be engraved, cast, or stamped.
7) All markings must be to a minimum depth of .003 of an inch as measured from the flat metal surface.
8) The serial number must be in a print size no smaller than 1/16th of an inch.
9) There is no specific statutory or regulatory height requirement for the remaining information other than it be ‘legible’. However, most NFA collectors choose to engrave the manufacturer’s name, city, and state in a 1/16th print size as well.
10) Laser engraving is an amazing process and can result in beautiful work on your firearm but make sure that any laser engraving shop you select is capable of meeting the depth requirements above.
ATF Ruling 2013-3 allows for the ‘adoption’ of existing markings