Specification guide
AMS7276 Specification Explained
What AMS7276 is: the SAE fluorocarbon (FKM) material specification behind the AS3209 and AS83248/1 O-rings and the AS3208 seals for aircraft fuel and engine oil systems, its status, hardness and qualification, and what an RFQ states.
AMS7276 is the SAE Aerospace Material Specification for fluorocarbon (FKM) rubber seals in aircraft fuel systems and specific engine oil systems: high-temperature fluid resistant, very low compression set, 70 to 80 Type A hardness. It is the live document behind a common aerospace Viton® callout, the successor to the cancelled MIL-R-83248 Class 1 material, and the specification that the SAE part standards AS3209, AS3208 and AS83248/1 invoke. The O-ring sheets AS3209 and AS83248/1 carry AS568 dash numbers. This guide covers what the document is, the part numbers that carry it, the material behind it, and what an RFQ needs to state. To order a specific part by size, the M83248 part family page and the AS3209 part family page list the designators against the AS568 dimensions.
What the document is
| Item | Value | Source |
|---|---|---|
| Full title (SAE) | Rings, sealing, fluorocarbon rubber, high-temperature-fluid-resistant, very-low-compression-set, 70 to 80 | SAE Mobilus standard page for AMS7276, read 2026-09-25 |
| Title (DLA ASSIST) | Rubber: fluorocarbon (FKM) high temperature-fluid resistant low compression set, 70 to 80 Type A hardness, for seals in fuel systems and specific engine oil systems | ASSIST document record 105727, read 2026-09-24 |
| Status | Active on DLA ASSIST (adopted January 2023); current SAE revision AMS7276J (18 May 2020) | DLA ASSIST record read 2026-09-24; SAE Mobilus record read 2026-09-25 |
| Material | Fluorocarbon (FKM) | Document title |
| Hardness | 70 to 80 Type A | Document title |
| Qualified products list | Non-government QPL, not in the DLA database | ASSIST prints "Non-government QPL" for this document |
| Part standards that invoke it | AS3209 (the O-ring sheet), AS3208 (the seal sheet), AS83248/1 (the O-ring sheet SAE issued in 2014) | SAE Mobilus records for AS3209, AS3208 and AS83248/1, read 2026-09-24 |
| Supersedes, in practice | MIL-R-83248 (cancelled 21 June 2001) and its 75 A O-ring sheet MIL-R-83248/1 (cancelled 24 July 2008) | DLA ASSIST records 33573 and 33574; the 2001 record names AMS7276 first among its successors |
Two authorities print two titles for this one document, which is why the source is named beside each. Neither title carries a temperature.
Part numbers that carry AMS7276 material
| Part number form | Part standard | Sizes | Note |
|---|---|---|---|
| AS3209-XXX | SAE AS3209, "Packing, preformed, AMS 7276 O-ring"; AS3209C, stabilized August 2021 (last revised 2017) | AS568 three-digit dash sizes | The AS number carries the sizes, the AMS number the compound; designators by size on the AS3209 page |
| AS3208 plus dash | SAE AS3208, "Packing, preformed, AMS 7276 seal"; AS3208A, stabilized May 2020 | Sizes per the AS3208 sheet | Send the dash number exactly as the print shows it |
| AS83248/1-XXX | SAE AS83248/1, "O-ring molded from AMS7276 material" | AS568 dash sizes | Issued by SAE in 2014, after DoD cancelled MIL-R-83248/1 in 2008 and pointed future purchases to AS3209 (boss sizes to AS3208); DoD adopted it on 2025-11-03 |
| M83248/1-XXX | MIL-R-83248/1 (cancelled 2008) | AS568 dash sizes | Legacy part number still ordered; supplied to AMS7276; see the M83248 guide and the M83248 part family |
| AMS7278 callouts | AMS7278 (cancelled May 1995, SAE record) | Per the print | Still appears on older drawings; order to the print |
| AS3084, AS3085 plus dash | AMS7280 | Sizes per each sheet | AS3084 is the seal sheet and AS3085 the O-ring sheet (SAE titles); see the AMS7280 guide |
| AS3581-XXX | AMS7259 | AS568 dash sizes | The 85 to 95 A companion specification (successor to M83248/2) |
What material is it, and what can it take?
Fluorocarbon (FKM) rubber, the family covered in the Viton guide. The Parker® O-Ring Handbook (ORD 5700, section 2.2.7) rates standard FKM compounds for continuous service from -26 C (-15 F) to 204 C (400 F), with low-temperature grades to -46 C. For a static fuel seal in deeper cold, see fluorosilicone vs FKM. The document title names the service (aircraft fuels and specific engine oils, high temperature, very low compression set), and a specification is not a temperature: the handbook's caution is that spec limits do not necessarily represent operating limits, and the qualified compound's sheet governs. Compression set is the property the title leads with: AMS7276 compounds are formulated to keep their sealing force through long hot service, which is why the same document is invoked for engine oil seals as well as fuel.
How does AMS7276 differ from AMS7280 and AMS7259?
| Specification | Hardness | Part standards | Status | When you see it |
|---|---|---|---|---|
| AMS7276 | 70 to 80 A | AS3209, AS3208, AS83248/1 | Active, revision J (2020); non-government QPL | The current default aerospace fluorocarbon O-ring callout |
| AMS7280 | 70 to 80 A (FKM type) | AS3084, AS3085 | Cancelled January 1992 at revision F (SAE record) | Older drawings; one qualified compound often serves several documents (Parker pairs V1164-75 with AMS7276 and AMS-R-83248) |
| AMS7259 | 85 to 95 A | AS3581 | Active (2017); non-government QPL | High-pressure and extrusion-resistant seals; successor to M83248/2 |
| AMS7278 | 70 to 80 A (SAE title) | none named | Cancelled 1995 (SAE record) | Older drawings |
| AMS7379 | 70 to 80 A | per print | Current, revision A (2020); low-temperature FKM (a -40 C glass transition in the title) | Cold-soak fuel systems |
| AMS-R-83248 | Class 1 75 A, Class 2 90 A (Parker Table 8-3) | M83248/1, /2 | SAE re-issue of the MIL spec, revision A (2005), itself now cancelled (SAE record) | Prints that still name the MIL number |
Reading the revision letter and the qualification
A trailing letter on the document is a revision: AMS7276J is the 2020 revision of AMS7276, and a print that says AMS7276 with no letter accepts the current one unless the program freezes a revision. A trailing letter inside a part number is not a revision; on many suppliers' part numbers a trailing letter identifies a compound. Qualification is separate from both: a manufacturer whose compound has passed the document's tests is listed on the non-government qualified products list that DLA ASSIST records for AMS7276, and the certificate of conformance that ships with the part names that manufacturer and the document. A commercial FKM O-ring of the same size is the same polymer family but is not a qualified part, and the difference is exactly what an aerospace receiving inspector checks.
What should the RFQ state?
The part standard and dash number (AS3209-214, for example), or the AMS7276 material callout with the AS568 size, the quantity, the revision if the drawing names one, and the documentation required (certificate of conformance to AMS7276; the manufacturer's test report if the program requires it; lot traceability). If the drawing names M83248/1 instead, say whether the print allows AS3209 or AS83248/1 in its place; both call for AMS7276 material.
How Conquest Seal supplies it
When the print calls out a specification with a qualified products list, the part comes from a manufacturer on that list; Conquest supplies it as a distributor and provides the certification paperwork (certificate of conformance naming the specification and, where the manufacturer issues one, the test report). Orders are handled under Conquest Seal's AS9100D quality management system, whose certificate scope includes distribution; it is not a product qualification and is unrelated to any QPL. See aerospace and defense sealing.
Viton is a trademark of The Chemours Company; Parker is a trademark of Parker Hannifin Corporation. No affiliation or endorsement is implied.
Sources
- Parker O-Ring Handbook ORD 5700, Tables 8-3 and 8-4 (page 8-4, 8-5), read 2026-09-24
- AMS 7276
- AMS-R-83248
- AMS7259
- AMS7278
- AMS7280
- AMS7379
- AS3084
- AS3085
- AS3208
- AS3209
- AS3581
- AS568
- AS83248
- DLA ASSIST
- MIL-R-83248
- SAE Mobilus
- SAE Mobilus records for AMS7278 and AMS7379, read 2026-09-25; AS3208 and AMS-R-83248, read 2026-09-24
- SAE Mobilus current-revision records for AMS7280F, AS3208A, AS3209C and AS83248/1A, read 2026-09-27
- Parker O-Ring Handbook ORD 5700, section 2.2.7, read 2026-09-14
- DLA ASSIST document records 105727, 33573 and 33574, read 2026-09-24 and 2026-09-25; SAE-AS83248/1 (ident 286630, adopted 2025-11-03), read 2026-09-25; the MIL-R-83248/1A cancellation notice (Notice 5, 2008-07-24), read 2026-09-29
- SAE Mobilus records for AMS7276, AMS7287 and AMS7379, read 2026-09-25; AS3209, AS3208, AS83248/1 and AMS-R-83248, read 2026-09-24
Frequently asked questions
Is AMS7276 the same as Viton?
AMS7276 is a material specification; Viton is one polymer maker's trademark for FKM. An AMS7276 O-ring is fluorocarbon rubber that a listed manufacturer has qualified to the document's tests, whichever polymer source it uses.
Where is the qualified products list for AMS7276?
Not in the DLA database. DLA ASSIST records AMS7276 with a non-government qualified products list, and the certificate of conformance names the qualified manufacturer that made the part.
What is the difference between AS3209 and AMS7276?
AS3209 is the dimensional part standard (the O-ring sizes); AMS7276 is the material it is molded from. The AS number carries the sizes, the AMS number the compound.
Does AMS7276 replace M83248/1?
Yes, in material: the cancellation of MIL-R-83248 names AMS7276 as a successor. For the /1 O-ring sheet, DoD cancelled M83248/1 in 2008 and pointed future purchases to SAE AS3209 (boss sizes to AS3208), and SAE later issued AS83248/1 (2014), which DoD adopted on 2025-11-03; both are on AMS7276 material.
What temperature is an AMS7276 O-ring good for?
The document is a materials and test specification, not an operating limit. For the FKM family the Parker handbook (section 2.2.7) gives -26 C to 204 C; the qualified compound's sheet and the application govern.
Which part standards invoke AMS7276?
AS3209 (revision C, stabilized 2021), AS3208 (revision A, stabilized 2020) and AS83248/1 (revision A of 2016, reaffirmed 2021). When DoD cancelled the MIL-R-83248/1 slash sheet in 2008 it pointed future purchases to AS3209 (boss sizes to AS3208); SAE issued AS83248/1 later, in 2014, and DoD adopted it on 2025-11-03. AS3209 and AS83248/1 carry AS568 dash numbers, so an AS3209-214 has the same 0.984 in inside diameter and 0.139 in section as any -214; AS3208 is the seal sheet, so send its dash number exactly as the print shows it.
How does AMS7276 differ from AMS7259?
Hardness. AMS7276 covers 70 to 80 Shore A fluorocarbon and is the Class 1 successor for M83248/1; AMS7259 covers 85 to 95 Shore A and stands behind AS3581 and the old M83248/2 Class 2 parts. Both are active SAE documents with a non-government qualified products list.
What about the low-temperature fluorocarbon documents?
AMS7287 (revision A, 2022) and AMS7379 (revision A, 2020), per their SAE Mobilus records read 2026-09-25, are 70 to 80 hardness fluorocarbon specifications whose titles state a glass transition of -30 C and -40 C respectively, for cold-start service that standard AMS7276 material does not cover; the cancelled MIL-R-83485 low-temperature family lives on as AMS-R-83485. The Parker handbook puts low-temperature FKM grades to -46 C.
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