The Ring,retaining,optical Element, cataloged under National Stock Number 1240-01-171-8377, is classified within Federal Supply Class 1240 (Optical Sighting and Ranging Equipment) of the Fire Control Equipment group. The manufacturer of record is Lockheed Martin Corporation. Government technical data includes 14 specifications, cited from the U.S. Government catalog. The record lists 1 manufacturer part number for this item, enabling identification through both NSN and commercial part number lookups. 1 additional reference document (drawings, advisory and superseded references) is recorded in the U.S. Government catalog. 1 item shares a part number with this NSN in the catalog (possible match — not a government interchangeability claim). Current acquisition status: Active.
| Parameter | Value |
|---|---|
| NSN | 1240-01-171-8377 |
| Primary Part Number | 13075287 |
| Item Name | Ring,retaining,optical Element |
| FSC / FSG | 1240 / 12 — Optical Sighting and Ranging Equipment |
| Manufacturer | Lockheed Martin Corporation |
| Status | ACTIVE |
| Groove Location | INSIDE END OF THREAD |
| Internal Flange Thickness | 0.543 INCHES NOMINAL IN |
| Groove Diameter | 4.820 INCHES NOMINAL IN |
| Thread Pitch Diameters | +4.7297 TO 4.7358 INCHES IN |
| Outside Diameter | 5.020 INCHES NOMINAL IN |
| Thread Length | 0.680 INCHES IN |
| Thread Location | INTERNAL |
| Aperture Diameter | 4.277 INCHES NOMINAL IN |
| Thread Direction | RIGHT-HAND |
| Inner Groove Width | 0.050 INCHES NOMINAL IN |
| Thread Size | 4 3/4-32 |
| Screw Thread Series Designator | UNS |
| Thread Class | 2B |
| Material | ALUMINUM ALLOY |
| Acquisition Status | ACTIVE |
| DEMIL Code | DEMIL A — No Demilitarization Required |
| Hazard | No hazard code in the DLA record (HMIC N) |
| Criticality Code | N |
| Part Number | Manufacturer |
|---|---|
| 13075287 | Lockheed Martin Corporation (USA) |
| Reference | Meaning |
|---|---|
| 13075287 | 3/9 Design control — primary reference Program Manager Advanced Attack Helicopter Barcom Amcpm-Aah |
NSN 1240-01-171-8377 is a Ring,retaining,optical Element, manufactured by Lockheed Martin Corporation, classified under FSC 1240, Optical Sighting and Ranging Equipment. Status: active.
NSN 1240-01-171-8377 has 1 manufacturer part number on file: 13075287 (Lockheed Martin Corporation).
1 possible match (shared part number, not a government interchangeability claim): 1375-01-675-2830. Verify interchangeability with system specifications before substitution.
Key specifications for 13075287: Groove Location: INSIDE END OF THREAD; Internal Flange Thickness: 0.543 INCHES NOMINAL IN; Groove Diameter: 4.820 INCHES NOMINAL IN; Thread Pitch Diameters: +4.7297 TO 4.7358 INCHES IN. 14 specifications are documented in the U.S. Government catalog.
No hazard code in the DLA record (HMIC N). Hazard information on this page is shown exactly as it appears in the DLA record.
U.S. Government catalog: edition PUBLOGDVD v12.0.0 (OCT 2026), edition date 2026-10-01, retrieved 2026-10-16.
U.S. Government catalog: edition PUBLOGDVD v12.0.0 (OCT 2026), edition date 2026-10-01, retrieved 2026-10-18.