The Nut,plain,castellated,hexagon, cataloged under National Stock Number 5310-00-943-5378, is classified within Federal Supply Class 5310 (Nuts and Washers) of the Hardware and Abrasives group. The manufacturer of record is Mcmellon Bros., Incorporated Dba Mc Mellon Brothers Inc. 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. Current acquisition status: Active.
| Parameter | Value |
|---|---|
| NSN | 5310-00-943-5378 |
| Primary Part Number | MCM320-2116 |
| Item Name | Nut,plain,castellated,hexagon |
| FSC / FSG | 5310 / 53 — Nuts and Washers |
| Manufacturer | Mcmellon Bros., Incorporated Dba Mc Mellon Brothers Inc |
| Status | ACTIVE |
| Width Across Flats | 1.937 INCHES MINIMUM AND 2.002 INCHES MAXIMUM IN |
| Surface Treatment Document and Classification | QQ-P-416,TY 2,CL 3 FED SPEC SINGLE TREATMENT RESPONSE OVERALL |
| Thread Series | UN |
| Hardness Rating | 26.0 ROCKWELL C MINIMUM AND 33.0 ROCKWELL C MAXIMUM |
| Material Document and Classification | MIL-S-6758 MIL SPEC 1ST MATERIAL RESPONSE OR MIL-S-5000 MIL SPEC 2ND MATERIAL RESPONSE OVERALL |
| Thread Direction | RIGHT-HAND |
| Nominal Thread Size | 1.312 INCHES IN |
| Nut Height | 0.656 INCHES NOMINAL IN |
| Surface Treatment | CADMIUM OVERALL |
| Nut Style | CASTELLATED, HEXAGON |
| Thread Class | 3B |
| Thread Quantity Per Inch | 16 |
| Material | STEEL COMP 4130 OR STEEL COMP 4340 OVERALL |
| Bearing Surface Type | WASHER FACED |
| Acquisition Status | ACTIVE |
| DEMIL Code | DEMIL A — No Demilitarization Required |
| Hazard | No hazard code in the DLA record (HMIC N) |
| Criticality Code | F |
| Part Number | Manufacturer |
|---|---|
| MCM320-2116 PRIMARY | Mcmellon Bros., Incorporated Dba Mc Mellon Brothers Inc (USA) |
NSN 5310-00-943-5378 is a Nut,plain,castellated,hexagon, manufactured by Mcmellon Bros., Incorporated Dba Mc Mellon Brothers Inc, classified under FSC 5310, Nuts and Washers. Status: active.
NSN 5310-00-943-5378 has 1 manufacturer part number on file: MCM320-2116 (Mcmellon Bros., Incorporated Dba Mc Mellon Brothers Inc).
Key specifications for MCM320-2116: Width Across Flats: 1.937 INCHES MINIMUM AND 2.002 INCHES MAXIMUM IN; Surface Treatment Document and Classification: QQ-P-416,TY 2,CL 3 FED SPEC SINGLE TREATMENT RESPONSE OVERALL; Thread Series: UN; Hardness Rating: 26.0 ROCKWELL C MINIMUM AND 33.0 ROCKWELL C MAXIMUM. 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.