The Bolt,shoulder, cataloged under National Stock Number 5306-00-401-7978, is classified within Federal Supply Class 5306 (Bolts) of the Hardware and Abrasives group. The manufacturer of record is Huck International, Inc. Government technical data includes 17 specifications, cited from the U.S. Government catalog. The record lists 7 manufacturer part numbers for this item, enabling identification through both NSN and commercial part number lookups. 4 additional reference documents (drawings, advisory and superseded references) are recorded in the U.S. Government catalog. Current acquisition status: Active.
| Parameter | Value |
|---|---|
| NSN | 5306-00-401-7978 |
| Primary Part Number | BACB30KK8-4 |
| Item Name | Bolt,shoulder |
| FSC / FSG | 5306 / 53 — Bolts |
| Manufacturer | Huck International, Inc |
| Status | ACTIVE |
| Head Height | 0.059 INCHES MINIMUM AND 0.069 INCHES MAXIMUM IN |
| Fastener Length | 0.645 INCHES NOMINAL IN |
| Shoulder Length | 0.740 INCHES MINIMUM AND 0.760 INCHES MAXIMUM FIRST SHOULDER IN |
| Shoulder Diameter | 0.279 INCHES MINIMUM AND 0.280 INCHES MAXIMUM FIRST SHOULDER IN |
| Thread Length | 0.395 INCHES MINIMUM IN |
| Shoulder Shape | ROUND FIRST SHOULDER |
| Hardness Rating | 31.0 ROCKWELL C NOMINAL OVERALL |
| Material Document and Classification | MIL-S-6758 MIL SPEC 1ST MATERIAL RESPONSE OR MIL-S-6050 MIL SPEC 2ND MATERIAL RESPONSE OR MIL-S-6098 MIL SPEC 3RD MATERIAL RESPONSE OR MIL-S-6049 MIL SPEC 4TH MATERIAL RESPONSE OVERALL |
| Nominal Thread Diameter | 0.250 INCHES IN |
| Head Style | FLAT CHAMFER |
| Thread Direction | RIGHT-HAND |
| Surface Treatment | CADMIUM OVERALL |
| Thread Class | 3A A |
| Thread Quantity Per Inch | 28 |
| Material | STEEL COMP 4130 OR STEEL COMP 8630 OR STEEL COMP 8735 OR STEEL COMP 8740 OVERALL |
| Thread Series Designator | UNIFIED NATIONAL JOINT FINE (UNJF) |
| Head Diameter | 0.387 INCHES MINIMUM AND 0.412 INCHES MAXIMUM 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 |
|---|---|
| BACB30KK8-4 | Huck International, Inc (USA) |
| BACB30KK8-4 | Sps Technologies, Llc Dba Air Industries Company Div Air Industries Company (USA) |
| HL218-8-4 | Lisi Aerospace Canada Corp Div Hi Shear Holdings Inc (CAN) |
| HL218-8-4 | Hi-Shear Corporation (USA) |
| HL218-8-4 | Howmet Global Fastening Systems Inc (USA) |
| BACB30KK8-4 | West Coast Aerospace, Inc. (USA) |
| 65960-8-4 | Sps Technologies, Llc Dba PB Fasteners (USA) |
| Reference | Meaning |
|---|---|
| HL218-8-4 | 5/9 Secondary reference Sps Technologies, Llc Dba PB Fasteners |
| BACB30KK8-4 | 3/2 Design control — primary reference U.S. Government activity |
| HL218-8-4 | 5/9 Secondary reference U.S. Government activity |
| BACB30KK8-4 | 5/2 Secondary reference U.S. Government activity |
NSN 5306-00-401-7978 is a Bolt,shoulder, manufactured by Huck International, Inc, classified under FSC 5306, Bolts. Status: active.
NSN 5306-00-401-7978 has 7 manufacturer part numbers on file: BACB30KK8-4 (Huck International, Inc), BACB30KK8-4 (Sps Technologies, Llc Dba Air Industries Company Div Air Industries Company), HL218-8-4 (Lisi Aerospace Canada Corp Div Hi Shear Holdings Inc), HL218-8-4 (Hi-Shear Corporation), HL218-8-4 (Howmet Global Fastening Systems Inc) and 2 more.
Key specifications for BACB30KK8-4: Head Height: 0.059 INCHES MINIMUM AND 0.069 INCHES MAXIMUM IN; Fastener Length: 0.645 INCHES NOMINAL IN; Shoulder Length: 0.740 INCHES MINIMUM AND 0.760 INCHES MAXIMUM FIRST SHOULDER IN; Shoulder Diameter: 0.279 INCHES MINIMUM AND 0.280 INCHES MAXIMUM FIRST SHOULDER IN. 17 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.