Prior to 1969 some mil experimentals were made with no serial numbers, and there are duplicate serial numbers in this area as well. A lot of the GXs have serial numbers in the 14xxx range. There are also GXs thatÂ alsoÂ have a serial number as well as the GX number. We believe that there are multiple GXs with the same number. GX’s are tool-room prototypes with a four digit number which is reportedly their master drawing. We have observed GX’s outside this range. The 10,000 guns in the 900k range are believed to include mostÂ experimental GX guns andÂ allÂ XM177/E1/E2 guns.The Model 04 Air Force Rifle is rollmarked M16.

(The nature of mass production being what it is, this rollmark change took place over a period of months, and is uncorrelated with any physical change to the rifle).

The Model 03 Army Rifle was rollmarked XM16E1 until the rifle was type standardized as M16A1 on.

The first ~15,000 guns were, as the memo notes, marked as “Armalite AR-15” and these weapons went to the USAF for Security Police use and for testing by the services, including the Project AGILE tests and Vietnam tests by USSF.

The first few Colt serial numbers (001-100) were toolroom prototypes and mules, and numbers were reused, and some were built on unnumbered receivers.

The complete text is below this editorial comment. The PDF is here: M16 Serial Number List OCR. We’ve OCR’d the PDF, and double-checked the numbers against the original data. This memo’s been around as a scanned, non-OCR’d.

Colt sp1 serial numbers