PartsTable TECHNICAL DATA SHEET
JULY 2026Technical Data Sheet

MS28778-3O-Ring

Leonardo Spa Aeronautics Division - Pomigliano D'arco Site · NSN 5331-00-931-6756 · FSC 5331 · O-Ring
Verified by PartsTable
NSN 5331-00-931-6756 — this item is cataloged by the U.S. Government under National Stock Number 5331-00-931-6756. Primary manufacturer part number: MS28778-3.
Features
  • O-Ring — FSC 5331
  • Temp Rating: -65.0 FAHRENHEIT AND 160.0 FAHRENHEIT DEGF
  • Center Hole Diameter: 0.296 INCHES MINIMUM AND 0.306 INCHES MAXIMUM IN
  • Elongation Percentage: 80 MAXIMUM
  • Material: PLASTIC POLYTETRAFLUOROETHYLENE
  • Hardness Rating: 90.0 SHORE DUROMETER A NOMINAL
  • Cross-Sectional Height: 0.061 INCHES MINIMUM AND 0.067 INCHES MAXIMUM IN
  • Outside Diameter: 0.429 INCHES NOMINAL IN
Applications
  • Fluid containment and leak prevention
  • Pressure boundary maintenance
  • Environmental sealing
  • Applications requiring Plastic Polytetrafluoroethylene construction
General Description

The O-Ring, cataloged under National Stock Number 5331-00-931-6756, is classified within Federal Supply Class 5331 (O-Ring) of the Hardware and Abrasives group. The primary manufacturer of record is Leonardo Spa Aeronautics Division - Pomigliano D'arco Site. Government technical data includes 7 verified specifications, sourced from the Federal Logistics Information System (FLIS). This item has 8 commercial cross-references from 8 manufacturers, enabling identification through both NSN and commercial part number lookups. 1 verified substitute exists in the FLIS interchangeability database. Current acquisition status: Active.

Technical Specifications
ParameterValue
NSN5331-00-931-6756
Primary Part NumberMS28778-3
Item NameO-Ring
FSC / FSG5331 / 53 — O-Ring
ManufacturerLeonardo Spa Aeronautics Division - Pomigliano D'arco Site
StatusACTIVE
Temp Rating-65.0 FAHRENHEIT AND 160.0 FAHRENHEIT DEGF
Center Hole Diameter0.296 INCHES MINIMUM AND 0.306 INCHES MAXIMUM IN
Elongation Percentage80 MAXIMUM
MaterialPLASTIC POLYTETRAFLUOROETHYLENE
Hardness Rating90.0 SHORE DUROMETER A NOMINAL
Cross-Sectional Height0.061 INCHES MINIMUM AND 0.067 INCHES MAXIMUM IN
Outside Diameter0.429 INCHES NOMINAL IN
Lifecycle & Compliance
Acquisition StatusACTIVE
HAZMATNo
Verified Substitutes 1
5331-00-835-7485LS4634-3 INTERCHANGEABLE
O-Ring
Lockheed Martin Corp
Cross-Reference Index
Part NumberManufacturer
MS28778-3 Leonardo Spa Aeronautics Division - Pomigliano D'arco Site (ITA)
SP202D903 Honeywell International Inc. Div Aerospace - Torrance (USA)
5331PL0899171 Jednolity Indeks Materialowy - Uniform Material Index (POL)
MS28778-3 Military Standards Promulgated by Military Departments Under Authority of Defense Standardization Manual 4120 3-M
MS28778-3 Sae International Dba Sae International (USA)
MS28778-3 Society of Automotive Engineers Inc (USA)
MS28778-3ES Eriks B.v. (NLD)
AS568A-903 Clark Gasket Co., Inc. (USA)
Related Parts
5331-00-835-7485INTERCHANGEABLE
O-RING
LS4634-3

Frequently Asked Questions

What is NSN 5331-00-931-6756?

NSN 5331-00-931-6756 is a O-Ring, manufactured by Leonardo Spa Aeronautics Division - Pomigliano D'arco Site, classified under FSC 5331 (O-Ring). Status: active.

What are the part numbers for NSN 5331-00-931-6756?

NSN 5331-00-931-6756 has 8 cross-referenced part numbers: MS28778-3 (Leonardo Spa Aeronautics Division - Pomigliano D'arco Site), SP202D903 (Honeywell International Inc. Div Aerospace - Torrance), 5331PL0899171 (Jednolity Indeks Materialowy - Uniform Material Index), MS28778-3 (Military Standards Promulgated by Military Departments Under Authority of Defense Standardization Manual 4120 3-M), MS28778-3 (Sae International Dba Sae International) and 3 more.

What NSN replaces 5331-00-931-6756?

There is 1 known substitute for 5331-00-931-6756: 5331-00-835-7485. Verify interchangeability with system specifications before substitution.

What are the specifications of MS28778-3?

Key specifications for MS28778-3: Temp Rating: -65.0 FAHRENHEIT AND 160.0 FAHRENHEIT DEGF; Center Hole Diameter: 0.296 INCHES MINIMUM AND 0.306 INCHES MAXIMUM IN; Elongation Percentage: 80 MAXIMUM; Material: PLASTIC POLYTETRAFLUOROETHYLENE. 7 total characteristics are documented in the Federal Logistics Information System.

Validated with multiple authoritative sources, including Government, OEM, and Certified sources.
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