Specification guide
M83248 Specification: /1 vs /2 and the SAE Successors
An M83248 O-ring is a fluorocarbon (FKM) O-ring called out as M83248/1-XXX (Class 1, 75 Shore A) or M83248/2-XXX (Class 2, 90 Shore A), where the three-digit dash is the AS568 size. MIL-R-83248, the military specification behind the number, was cancelled in 2001 and superseded by SAE documents; the part number is still ordered every day, and the live material specification behind an M83248/1 ring is SAE AMS7276.
M83248 is the part-number family for fluorocarbon (FKM) O-rings originally specified by MIL-R-83248, the military specification for high-temperature, fluid-resistant, compression-set-resistant fluorocarbon rubber used in aircraft fuel, lubricant and hydraulic systems. Parts are called out as M83248/1-XXX (Class 1, 75 Shore A) and M83248/2-XXX (Class 2, 90 Shore A), where the three-digit dash number is the AS568 size. The military document was cancelled in 2001 and superseded by four SAE documents, but the part numbers remain in daily use on drawings and purchase orders, and the live material specification behind an M83248/1 O-ring today is SAE AMS7276. This guide decodes the callout, gives the document lineage as it stands in the government and SAE records, and says what an RFQ needs to state.
To order by dash number, the family page M83248 O-rings by dash number lists the sizes; this guide covers the specification behind them.
What does an M83248 part number mean?
| Element | Example | Meaning |
|---|---|---|
| Base number | M83248 | The part family under MIL-R-83248; M is the military part-number prefix |
| Slash sheet | /1 or /2 | /1 = Class 1, 75 Shore A fluorocarbon; /2 = Class 2, 90 Shore A fluorocarbon |
| Dash number | -214 | The AS568 size (0.984 in ID x 0.139 in CS for -214); see the dash number guide |
| Full example | M83248/1-214 | A 75 A fluorocarbon O-ring, AS568-214 size, to the Class 1 requirements |
| Material behind it today | AMS7276 (for /1), AMS7259 (for /2) | SAE material specifications the DLA ASSIST record names among MIL-R-83248's successors |
| SAE O-ring sheets | SAE AS3209 and SAE AS83248/1 (for /1); SAE AS3581 and SAE AS83248/2 (for /2) | For /1, DoD cancelled M83248/1 in 2008 and pointed future purchases to AS3209 (boss sizes to AS3208), and SAE later issued AS83248/1 (2014), titled O-ring molded from AMS7276 material, which DoD adopted on 3 November 2025; for /2 the records name two SAE documents; both are set out with their dates under Document lineage below |
Document lineage: what is cancelled and what the records name next
Statuses and supersession below are read from the DLA ASSIST document records (read 2026-09-24, 2026-09-25, 2026-09-28 and 2026-09-29) and the SAE Mobilus records (read 2026-09-24, 2026-09-27 and 2026-09-28), each named in the sources. A cancelled document is still a live part number: buyers keep ordering M83248/1 by that number, and the right answer is which current document governs, never that the part does not exist.
| Document | Title (as printed) | Status | What the records name next |
|---|---|---|---|
| MIL-R-83248 | Rubber, fluorocarbon elastomer, high temperature, fluid, and compression set resistant | Cancelled 21 June 2001 (last revision C, 1994) | Superseded by SAE AMS7276, AMS7259, AMS3216 and AMS3218 |
| MIL-R-83248/1 | O-rings, Class 1, 75 hardness | Cancelled 24 July 2008 (Notice 5) | Notice 5 pointed future purchases to SAE AS3209 and those of the boss sizes (M83248/1-901 to -932) to SAE AS3208, and cautions users to evaluate a replacement for their own application. SAE later issued AS83248/1, titled "O-ring molded from AMS7276 material", in December 2014 (current revision A, reaffirmed November 2021), and DoD adopted it on 3 November 2025 |
| MIL-R-83248/2 | O-rings, Class 2, 90 hardness | Cancelled 22 January 2004 | Superseded by SAE AS3581 and SAE AMS7259, as the DLA ASSIST record's title names them (AS3581's current revision, AS3581A, was stabilized in May 2020). SAE also issued AS83248/2, O-ring molded from AMS7259 material (current revision AS83248/2A, reaffirmed November 2021), which DoD adopted on 3 November 2025 |
| SAE AMS-R-83248 | Rubber, fluorocarbon elastomer, high temperature, fluid, and compression set resistant | Cancelled; SAE's record lists revision A (published 2005-09-22) as the last, with the status Canceled; it was the SAE re-issue of the MIL spec | none named in SAE's record |
| SAE AMS7276 | 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 | Active; SAE's current revision AMS7276J (2020) | none; qualified products list held by SAE |
| SAE AMS7259 | Fluorocarbon (FKM) rubber, 85 to 95 hardness, for seals in fuel systems and specific engine oil systems | Active; adopted by DoD 17 August 2017 (DLA ASSIST) | none; qualified products list held by SAE |
| SAE AMS3216, AMS3218 | Fluorocarbon (FKM) rubber, 70 to 80 hardness for products and 85 to 95 hardness for seals, in fuel systems and specific engine oil systems | Current, revisions J (October 2023) and E (November 2023) | none |
A prefix change is not a new document: a print that reads MIL-R-83248 refers to the same cancelled record whatever letters it carries. Trailing letters on the document (AMS7276J, AS83248/1A) are revisions; a trailing letter inside a part number is not.
What material is it, and what can it take?
Both classes are fluorocarbon (FKM) rubber, the family covered in the Viton® guide. The Parker O-Ring Handbook (ORD 5700) rates standard FKM compounds for continuous service from -26 C (-15 F) to 204 C (400 F), with low-temperature grades to -46 C (-51 F) and short excursions above 204 C; the qualified compound's own sheet governs. The specification titles describe the service, high-temperature fuel and oil resistance with low compression set, and a specification is not a temperature: the Parker handbook's own caution is that spec temperature limits do not necessarily represent operating limits. Class 1 (75 A) is the general aerospace fuel and lubricant seal; Class 2 (90 A) is for high pressure and extrusion resistance. Parker's handbook shows one compound serving several of these documents: its Table 8-3 pairs V0747-75, V1164-75 and V1226-75 with MIL-R-83248 Type I Class 1 and V0709-90 with Class 2, and its Table 8-4 pairs V1164-75 with AMS7276 and V0709-90 with AMS7259.
Related callouts you will see on the same drawings
| Callout | Material | Hardness | Relationship |
|---|---|---|---|
| AS3209-XXX, AS3208-YY | FKM to AMS7276 | 75 A | The SAE part standards for AMS7276: AS3209 is the O-ring sheet, in the AS568 dash sizes, and AS3208 the seal sheet, in the sizes on its own sheet |
| AS3581-XXX | FKM to AMS7259 | 90 A | The successor part standard for M83248/2 |
| AS3084, AS3085 | FKM to AMS7280 | 75 A | The older SAE fluorocarbon O-ring standard; see the AMS7280 guide |
| M83485/1-XXX | FKM to AMS-R-83485 | 75 A | Low-temperature (GLT-type) fluorocarbon |
| MS28775-XXX | Nitrile to MIL-PRF-25732 | 75 A | The petroleum hydraulic O-ring, often on the same drawing; a different material |
| M25988/1-XXX | Fluorosilicone to AMS-R-25988 | 70 A | Fuel seals at low temperature |
The mil-spec O-ring chart lists the full set and the AMS7276 guide covers the live material specification.
What should the RFQ state?
The full part number (M83248/1-214, AS3209-214 or AS83248/1-214, as the print names it), the quantity, whether the print allows an SAE document in place of the MIL number, and the documentation required: a certificate of conformance to the specification, the manufacturer's test report if the program needs it, and lot traceability. If the drawing carries a revision letter, quote it; if it carries a compound number as well, quote that too. A drawing that names MIL-R-83248 with no revision and no "or equivalent" is still answerable: the current document is AMS7276 (or AMS7259 for Class 2), and the certificate names both.
How Conquest Seal supplies it
Parts to these documents are made by manufacturers on the relevant qualified products list, where the document has one; Conquest supplies them as a distributor and provides the certification paperwork (certificate of conformance naming the specification and, where the manufacturer issues one, the test report). Conquest's quality management system handles the order and the paperwork; 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. No affiliation or endorsement is implied.
Sources
- Parker O-Ring Handbook ORD 5700, section 2.2.7 (fluorocarbon heat and cold figures), read 2026-09-14
- DLA ASSIST document details: MIL-R-83248 (ident 33573), read 2026-09-25; MIL-R-83248/1 (ident 33574), SAE-AMS7276 (ident 105727) and SAE-AMS7259 (ident 105726), read 2026-09-24; the MIL-R-83248/1A cancellation notice (Notice 5, 2008-07-24), read 2026-09-29; SAE-AS83248/1 (ident 286630), read 2026-09-25; MIL-R-83248/2 (ident 33575) and SAE-AS83248/2 (ident 286631), read 2026-09-28
- SAE Mobilus current-revision records: AMS7276J, AMS3216J, AMS3218E, AS83248/1A, AS3208A and AS3209C, read 2026-09-27; AS3581A and AS83248/2A, read 2026-09-28
- SAE Mobilus record for AMSR83248A (status Canceled; revisions AMSR83248, 1999-04-01, and AMSR83248A, 2005-09-22), read 2026-09-24
- AMS7280, AMS-R-83485, AMS-R-25988, AS3084, AS3085, MS28775 and MIL-PRF-25732, named as callouts
- Parker O-Ring Handbook ORD 5700 (2021 printing), Tables 8-3 and 8-4 (compound pairings), read 2026-09-24
Frequently asked questions
Is MIL-R-83248 still valid?
The document was cancelled in 2001, with SAE AMS7276, AMS7259, AMS3216 and AMS3218 named as its successors, and its /1 sheet in 2008, when DoD pointed future purchases to SAE AS3209 (boss sizes to AS3208); SAE later issued AS83248/1 (2014), O-ring molded from AMS7276 material, which DoD adopted on 3 November 2025. The part number M83248/1-XXX is still valid as an order line and still appears on drawings; it is supplied to the current SAE documents.
Is it MIL-DTL-83248 or MIL-R-83248?
MIL-R-83248. The DTL prefix belongs to other families (MIL-DTL-25988 fluorosilicone, for example); the 83248 record never carried it.
What is the difference between /1 and /2?
Hardness. /1 is Class 1, 75 Shore A, the general fuel and lubricant seal; /2 is Class 2, 90 Shore A, for high pressure and extrusion resistance. See the durometer guide.
Can I substitute a commercial Viton O-ring?
Only if the print allows it. A qualified part is made by a manufacturer on the qualified products list to the specification's tests; a commercial FKM ring of the same size is the same polymer family but not the same qualification.
Does the dash number change with the specification?
No. -214 is the same AS568 size whether the prefix is M83248/1, AS3209 or 2-. The AS568 chart has the dimensions.
Which four SAE documents replaced MIL-R-83248?
The DLA ASSIST record's title names AMS7276, AMS7259, AMS3216 and AMS3218: AMS7276 and AMS3216 cover the 70 to 80 hardness band and AMS7259 and AMS3218 the 85 to 95 band, all fluorocarbon for fuel systems and specific engine oil systems. AMS3216 is at revision J (2023) and AMS3218 at revision E (2023).
What are the current part standards for the two slash sheets?
For /1, DoD cancelled M83248/1 in 2008 and pointed future purchases to SAE AS3209, whose current revision, AS3209C, was stabilized in August 2021 (boss sizes to SAE AS3208); SAE later issued AS83248/1 (2014), titled O-ring molded from AMS7276 material (revision A, reaffirmed November 2021), which DoD adopted on 3 November 2025. For /2 the records name two SAE documents: DLA ASSIST records MIL-R-83248/2 as cancelled on 22 January 2004 and superseded by SAE AS3581 and SAE AMS7259, and AS3581's current revision, AS3581A, was stabilized in May 2020; SAE also issued AS83248/2, O-ring molded from AMS7259 material, whose current revision AS83248/2A (revised October 2016, reaffirmed November 2021) DoD adopted on 3 November 2025. Drawings still carry the M numbers, and the part is quoted against the number the print names.
Is there a qualified products list for the M83248 family today?
The qualification lives with the SAE material documents: AMS7276 and AMS7259 each carry a non-government qualified products list maintained through SAE, and the cancelled military document's list no longer governs. A certificate from a manufacturer on that list is what an order for M83248/1 parts should ask for.
Related guides
Orders are handled under Conquest Seal's AS9100D quality management system, whose certificate scope includes distribution.
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