"Depending upon one's location, NSN stands for National or NATO stock number. The designation is derived from the former US Federal Stock Numbers (FSNs). The FSN was introduced in 1952 as part of the Defense Cataloging and Standardization Act in an effort to implement the concept of a single-item identification number (e.g., all standard 40-watt light bulbs with the same function, regardless of manufacture, were assigned the same FSN). On September 30, 1974, FSNs were replaced with 13-digit NSNs. The two additional digits identified the nation that originated the item. These digits are called the National Codification Bureau (NCB) Code. The NSN (Versorgungsnummer in German) is broken down as follows:
| Federal Supply Class (FSC) | 1005 |
| National Codification Bureau Code (NCB) | 00 |
| Nonsignificant serial number | 123-4567 |
The NCB + seven digits = National Item Identification Number (NIIN). The FSC + NCB + seven digits = NSN. The last seven digits (non-significant serial number) are randomly assigned and have no significance."
Edward Clinton Ezell
Small Arms Today
Latest Reports on the World's Weapons and Ammunition
2nd Edition
Stackpole Books, Harrisburg, PA
1988
STACKPOLE INC (CAGE Code 40560)
