The Ring,piston, cataloged under National Stock Number 4310-00-131-5261, is classified within Federal Supply Class 4310 (Compressors and Vacuum Pumps) of the Pumps and Compressors group. The manufacturer of record is Circor Naval Solutions Llc Dba Warren Pumps. Government technical data includes 8 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through both NSN and commercial part number lookups. 1 additional reference document (drawings, advisory and superseded references) is recorded in the U.S. Government catalog. 4 items share a part number with this NSN in the catalog (possible match — not a government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 | 4310-00-131-5261 |
| Primary Part Number | SM-4 |
| Item Name | Ring,piston |
| FSC / FSG | 4310 / 43 — Compressors and Vacuum Pumps |
| Manufacturer | Circor Naval Solutions Llc Dba Warren Pumps |
| Status | ACTIVE |
| FSC Application Data | STEAM PISTON,DIRECT ACTING RECIPROCATING PUMP |
| Bore Diameter Oversize | 0.010 INCHES IN |
| Cross-Sectional Shape Style | PLAIN RECTANGULAR, STRAIGHT FACE |
| Joint Style | STEP JOINT |
| Radial Wall Thickness | 0.1150 INCHES MINIMUM AND 0.1250 INCHES MAXIMUM IN |
| Ring Style | CONCENTRIC |
| Standard Bore Diameter | 3.000 INCHES IN |
| Material | IRON OVERALL |
| 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 |
|---|---|
| SM-4 PRIMARY | Circor Naval Solutions Llc Dba Warren Pumps (USA) |
| Reference | Meaning |
|---|---|
| BS5-1703PC109 | 5/9 Secondary reference Circor Naval Solutions Llc Dba Warren Pumps |
NSN 4310-00-131-5261 is a Ring,piston, manufactured by Circor Naval Solutions Llc Dba Warren Pumps, classified under FSC 4310, Compressors and Vacuum Pumps. Status: active.
NSN 4310-00-131-5261 has 1 manufacturer part number on file: SM-4 (Circor Naval Solutions Llc Dba Warren Pumps).
4 possible matches (shared part number, not a government interchangeability claim): 4820-00-958-5213, 5961-01-153-8357, 3120-01-168-0912. Verify interchangeability with system specifications before substitution.
Key specifications for SM-4: FSC Application Data: STEAM PISTON,DIRECT ACTING RECIPROCATING PUMP; Bore Diameter Oversize: 0.010 INCHES IN; Overall Width: 0.1850 INCHES MINIMUM AND 0.1860 INCHES MAXIMUM IN; Cross-Sectional Shape Style: PLAIN RECTANGULAR, STRAIGHT FACE. 8 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.