NATO Stock Number

A NATO Stock Number, or National Stock Number (NSN) as it is known in the US, is a 13-digit numeric code, identifying all the 'standardized material items of supply' as they have been recognized by all NATO countries including United States Department of Defense. Pursuant to the NATO Standardization Agreements, the NSN has come to be used in all treaty countries, where it is also known as a NATO Stock Number. However, many countries that use the NSN program are not members of NATO, e.g. Japan, Australia and New Zealand. A two-digit Material Management Aggregation Code (MMAC) suffix may also be appended, to denote asset end use but it is not considered part of the NSN. An item having an NSN is said to be "stock-listed".

Structure


The format of an NSN might be described as follows:

abcd-ef-ghi-jklm

Each element, a through m, was originally intended to be a single decimal digit. As inventories grew in complexity, element g became alphanumeric, beginning with capital A for certain newly added items. By 2000, uppercase C was in use.

Federal Supply Classification Group (FSCG)
The initial subgroup, abcd, is the Federal Supply Classification Group (FSCG) or National Supply Classification Group (NSCG). In theory, similar items would always have closely related numbers in this section of the NSN, no matter how the section is referred to. As the number of items has steadily increased and the system has become more complicated, it has not always been possible to keep similarity in numbers when the items are similar.

National Item Identification Number
The nine digits, ef-ghi-jklm, comprise the NIIN (National Item Identification Number).

National Codification Bureau
The ef pair is used to record which country was the first to codify the item—which one first recognized it as an important item of supply. This is generally the country of origin, meaning the country of final manufacture. The formal name of the field is CC for Country Code or NCB, because NCB also stands for National Codification Bureau. According to this system, for example, US is 00 and 01, Japan 30, Saudi Arabia is 70, the UK is 99 and Australia is 66.

Department of Defense Identification Code (DODIC)
This is an alphanumeric four-symbol code consisting of two letters followed by two numerals. This code is shown either after the NSN or on the line underneath it on the container. The DODIC identifies the item, while the NSN identifies what type of item it is and how it is packaged and contained.

Sometimes The DODIC also contains a two-numeral NCB code prefix for the manufacturer's country if it is different from the packager's country. *AO59 is the DODIC code for 5.56mm NATO M855 Ball type ammunition. *Bulgaria has the NCB code number 50. **50-AO59 is Bulgarian-manufactured 5.56mm NATO ammunition equivalent to M855 Ball.

NATO Symbols

 * A container marked with a "square cross" in a circle means the item is made exactly to NATO standards and specifications.
 * A container marked with a rounded "Cross pattée" means it is a substitute item that is compatible and acceptable by NATO standards.
 * A solid circle indicates Ball Ammunition.
 * A empty circle with dashed lines indicates Blank Ammunition.
 * A horizontal straight line through vertical rectangles or cartridge shapes indicates linked ammunition.
 * Early US Military ammunition boxes were also marked with a B for cloth belts or L for metal link belts. When the symbol was straight it indicated .30 ammunition and when the symbol was angled it indicated .50 ammunition.

Lot Number
The Lot Number consists of the three-letter manufacturer's code, the two-numeral year of manufacture, and a batch code that consists of 1 or more numerals. It will contain either the manufacturer's three letter code or that of the repacker that subcontracted the lot. The year and batch number in the Lot Number will track down when it was made if a batch is faulty or defective.

History
The NSN is an expanded version of the older Federal Stock Number (FSN), which lacked the national-origin code labeled ef above, in the second subgroup. Items predating 1974 in warehouses are frequently stenciled with FSNs. As of 1998, the system is principally administered by the Defense Logistics Agency within the U.S. Department of Defense.

Other stock numbering systems are in use within the US DoD, but as of 2005, the NSN remained the most common and least ambiguous way to identify most standardized items of supply.

Federal Stock Number
A Federal Stock Number (FSN) was an 11-digit numeric code. It was first used by the Defense Munitions Board's Cataloging Agency in 1949 to identify items in the Joint Army-Navy Catalog System. The Federal Stock Number was used officially from 1953 to 1974, when it was replaced by the National Stock Number. The conversion from FSN to NSN was typically done by adding "00" between the first set of numbers (the Federal Supply Class, or FSC) and the second set of numbers.

For example, the FSN:

Fictionalized NSNs
It is not unheard of for certain numbers to be referred to in works of fiction as if they were NSNs—especially in military science fiction. This can be seen as a variation on the false document technique, something used creatively in order to lend an air of authenticity. For example, the M41A Pulse Rifle, from the movie Aliens, has been referred to as having NSN 3055-00-721-4790, as if it were real (though its FSG is incorrect: 30 is mechanical power transmission equipment, while 10, weapons, is probably the right FSC). The spacecraft hull repair kit that the player must use in the sci-fi computer game Mission Critical, to stop the decompression emergency, has "NSN 5920-385-19468" stenciled on  the side of its plastic box.