What is a National Stock Number (NSN)?

By Gordon Bonnes, Iowa PTAC

Do you know what a National Stock Number (NSN) is?

It’s a part number for a Department of Defense item that they buy a lot of. To understand it, let’s starts with a solicitation, and let’s look at two examples to help explain it.

First, the army buys a rifle. They like it so much that they expect that they will buy lots of these over a long period of time. In fact, they expect that they will use them so much, that they will need lots of replacement parts to keep them working in tip-top shape. So they start assigning Part Numbers and Sub-Assembly Numbers to the replacement pieces that they think they will want to order. These are not the part numbers on the manufacturing drawings. These are new numbers that are constructed from an inventory handling point of view.

In the second example, the navy uses a lot of ball point pens, so instead of issuing solicitations every few months for purchasing more pens, they decide on a specification for the pen (probably adopted in part from previous purchases) and create an NSN number for it. This makes it easier to buy them.

Now for each of these, at the depot/supply level, they find a spot to inventory them. Their plan is to keep an amount on hand so that they can distribute these on an as-needed basis with an immediate delivery. So they use the NSN number that they assigned to that item/part/sub-assembly for the troops to order more when they need them, and for the DoD when ordering more to keep the shelf full.

So notice that a manufactured part (a gear, pin, barrel, clip, etc.) is ideal for this system, but it is also used for commercial parts too (COTS – Commercial-Off-the-Shelf), like pens.

The Department of Defense uses this system, and it is administered by the DLA (Defense Logistics Agency). As you know, they are their buying department. You’ll also find that each of the services (Army, Navy, Air Force, Marines) have supply depots for their inventoried “stuff”, but that’s another topic for another week.

So how do they put an NSN together and how can you recognize it? Remember back when you started preparing to do federal government contracting and you had to pick out codes that described your industry and your products? You used NAICS codes to describe the industries that you were in, and you had an opportunity to pick out FSC codes for your products (Federal Supply Codes). These FSC codes are the beginnings of the NSN numbers. For instance a “bolt” is FSC code 5306, so this would be the beginning digits of the NSN number for any bolt. An NSN for a “pen” would start with 7510 for office supplies.

To help you further recognize these numbers, here is an example on an actual solicitation that refers to an NSN.

Click here for a really thorough description of how an NSN is put together. Take a look.

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 Gordon Bonnes Head shot

Gordon Bonnes has been a Government Contracting Specialist for the Iowa PTAC at Iowa State University’s Center for Industrial Research and Service (CIRAS) since 2010.  Prior to that, he enjoyed a 20 year career in manufacturing, sourcing and quality assurance.

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