National Stock Number
5305-01-172-0521
National Stock Number (NSN) 5305-01-172-0521, or NIIN 011720521, (screw,cap,hexagon head) was assigned February 15, 1984 in the Federal Logistics Information System (FLIS). This NIIN is Available for Manual Assignment. This NSN does not replace any other NSNs.
There are 3 manufacturer part numbers associated with this NSN. None of the associated part number(s) are considered obsolete. The manufacturer part numbers were originally supplied by one supplier. Today, one supplier is listed as an Active supplier for this NSN. Of the active suppliers, there are no suppliers that are deemed design controlled or valid supply parts.
This part number has not been procured by the US Government in over 5 years.
This NSN is somewhat common among different platforms, belonging to 5 different weapons systems.
Based on a planned procurement review by the Primary Inventory Control Activity (PICA) on Apr 12, 2013, this NSN's acquisition method was noted as: Acquire directly from the actual manufacturer, whether or not the prime contractor is the actual manufacturer. The data or the rights to use the data needed to purchase this part from additional sources are not owned by the Government and it has been determined that it is uneconomical to purchase them. Valid AMCs: 1, 2, 3, 4 and 5.
This NSN is assigned to Item Name Code (INC) 18257. [AN EXTERNALLY THREADED FASTENER DESIGNED FOR INSERTION INTO HOLES IN ASSEMBLED PARTS, FOR MATING WITH A PREFORMED INTERNAL THREAD AND FOR TIGHTENING OR RELEASING BY TORQUING THE HEAD. THE THREADED AND UNTHREADED PORTIONS ARE BOTH OF THE SAME NOMINAL DIAMETER OF 0.190 INCH (5 MM) OR LARGER. HEAD DIMENSIONS AND SIZES OF THREADED AND UNTHREADED PORTIONS SHALL CONFORM TO INTERNATIONALLY RECOGNIZED FASTENER STANDARDS. THE THREAD LENGTH BEING THE CONTROLLED DIMENSION, THE GRIP LENGTH IS NOT SPECIFIED. A LOCKING FEATURE MAY BE INCORPORATED IN THE DESIGN OF THE HEAD OR THREADS. THE HEAD IS NOT DESIGNED TO BE HELD OR DRIVEN WITH AN INSERTED DRIVER OR BY THE THUMB AND FINGERS. EXCLUDES:BOLT,MACHINE; BOLT,EXTERNALLY RELIEVED BODY; BOLT,INTERNAL WRENCHING; AND SCREW,CAP,SOCKET HEAD.]. This item does not have a nuclear hardened feature or any other critical feature such as tolerance, fit restriction or application. There is no data in the HMIRS and the NSN is in an FSC not generally suspected of containing hazardous materials. NSN 5305011720521 does not contain precious metals.
This information was last updated on Aug 01, 2025.