The Telescope Subassembly, cataloged under National Stock Number 1240-01-285-3504, is classified within Federal Supply Class 1240 (Optical Sighting and Ranging Equipment) of the Fire Control Equipment group. The manufacturer of record is Naval Sea Systems Command. Government technical data includes 2 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through both NSN and commercial part number lookups. 1 additional reference document (drawings, advisory and superseded references) is recorded in the U.S. Government catalog. 2 items share a part number with this NSN in the catalog (possible match — not a government interchangeability claim). Current acquisition status: Active.
| Parameter | Value |
|---|---|
| NSN | 1240-01-285-3504 |
| Primary Part Number | 5551258 |
| Item Name | Telescope Subassembly |
| FSC / FSG | 1240 / 12 — Optical Sighting and Ranging Equipment |
| Manufacturer | Naval Sea Systems Command |
| Status | ACTIVE |
| Component Type and Quantity | 2 PIN |
| Overall Diameter | 0.630 INCHES NOMINAL IN |
| Acquisition Status | ACTIVE |
| DEMIL Code | DEMIL D — Destroy Item |
| Hazard | No hazard code in the DLA record (HMIC N) |
| Criticality Code | X |
| Part Number | Manufacturer |
|---|---|
| 5551258 PRIMARY | Naval Sea Systems Command (USA) |
| Reference | Meaning |
|---|---|
| 55119 | 5/2 Secondary reference U.S. Government activity |
NSN 1240-01-285-3504 is a Telescope Subassembly, manufactured by Naval Sea Systems Command, classified under FSC 1240, Optical Sighting and Ranging Equipment. Status: active.
NSN 1240-01-285-3504 has 1 manufacturer part number on file: 5551258 (Naval Sea Systems Command).
2 possible matches (shared part number, not a government interchangeability claim): 5310-01-507-5009, 5120-01-718-1146. Verify interchangeability with system specifications before substitution.
Key specifications for 5551258: Component Type and Quantity: 2 PIN; Overall Diameter: 0.630 INCHES NOMINAL IN; Overall Length: 9.400 INCHES MINIMUM AND 15.750 INCHES MAXIMUM IN; Special Features: FOUR 0.196 IN. DIA MTG HOLES;LEG 1,LEG EXTENSION 1,MTG BRACKETS 2 IN. 2 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.
NSN 1240-01-285-3504 has DEMIL Code D. Demilitarization may be required before disposal or transfer to non-military entities.
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.