The Washer,flat, cataloged under National Stock Number 5310-01-591-1396, is classified within Federal Supply Class 5310 (Nuts and Washers) of the Hardware and Abrasives group. The manufacturer of record is Sikorsky Aircraft Corporation Dba Sikorsky Aircraft Corp. Government technical data includes 10 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through both NSN and commercial part number lookups. 3 additional reference documents (drawings, advisory and superseded references) are recorded in the U.S. Government catalog. 4 items share a part number with this NSN in the catalog (possible match — not a government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 | 5310-01-591-1396 |
| Primary Part Number | MS21299-12K |
| Item Name | Washer,flat |
| FSC / FSG | 5310 / 53 — Nuts and Washers |
| Manufacturer | Sikorsky Aircraft Corporation Dba Sikorsky Aircraft Corp |
| Status | ACTIVE |
| Surface Treatment Document and Classification | AMS 2700, METHOD I, CLASS 4 ASSN STD SINGLE TREATMENT RESPONSE OVERALL |
| Overall Diameter | 1.423 INCHES MINIMUM AND 1.433 INCHES MAXIMUM IN |
| Material Document and Classification | AMS 5604, 17-4PH, CONDITION H1025 ASSN STD SINGLE MATERIAL RESPONSE OVERALL |
| Cross-Sectional Shape Style | RECTANGULAR |
| Surface Treatment | PASSIVATE OVERALL |
| Peripheral Shape Style | ROUND |
| Material | STEEL COMP 630 OVERALL |
| Center Hole Shape Style | ROUND |
| Hole Diameter | 0.752 INCHES MINIMUM AND 0.756 INCHES MAXIMUM IN |
| Thickness | 0.062 INCHES NOMINAL IN |
| Acquisition Status | ACTIVE |
| DEMIL Code | DEMIL A — No Demilitarization Required |
| Hazard | No hazard code in the DLA record (HMIC N) |
| Criticality Code | X |
| Part Number | Manufacturer |
|---|---|
| MS21299-12K | Sikorsky Aircraft Corporation Dba Sikorsky Aircraft Corp (USA) |
| Reference | Meaning |
|---|---|
| MS21299-12K | 5/9 Secondary reference U.S. Government activity |
| NASM21299 | 4/1 Identification reference U.S. Government activity |
| MS21299-12K | 3/2 Design control — primary reference U.S. Government activity |
NSN 5310-01-591-1396 is a Washer,flat, manufactured by Sikorsky Aircraft Corporation Dba Sikorsky Aircraft Corp, classified under FSC 5310, Nuts and Washers. Status: active.
NSN 5310-01-591-1396 has 1 manufacturer part number on file: MS21299-12K (Sikorsky Aircraft Corporation Dba Sikorsky Aircraft Corp).
4 possible matches (shared part number, not a government interchangeability claim): 5310-01-666-2194, 5310-01-666-2199, 5310-01-713-4379. Verify interchangeability with system specifications before substitution.
Key specifications for MS21299-12K: Surface Treatment Document and Classification: AMS 2700, METHOD I, CLASS 4 ASSN STD SINGLE TREATMENT RESPONSE OVERALL; Overall Diameter: 1.423 INCHES MINIMUM AND 1.433 INCHES MAXIMUM IN; Material Document and Classification: AMS 5604, 17-4PH, CONDITION H1025 ASSN STD SINGLE MATERIAL RESPONSE OVERALL; Cross-Sectional Shape Style: RECTANGULAR. 10 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.