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MA6551P4-921 — SCREW,SHOULDER

✓ Government record, cited
— · BOLT SCREW
PRODUCT OVERVIEW

MA6551P4-921: SCREW,SHOULDER.

The SCREW,SHOULDER is a the manufacturer industrial component. Key specifications include material: STEEL COMP 4037 OVERALL, head_style: FLAT COUNTERSUNK, thread_class: 2A A, head_diameter: 0.357 INCHES NOMINAL IN, thread_length: 0.406 INCHES MINIMUM AND 0.436 INCHES MAXIMUM IN, shoulder_shape: ROUND FIRST SHOULDER. This part is cataloged in the U.S.

Government catalog under NSN 5305-00-151-8660, indicating validated use in U.S. government and defense logistics supply chains. Available through authorized enterprise resellers and TPM (Third Party Maintenance) channels.

Verify compatibility with your specific system configuration before ordering.

WHERE IT FITS
MA6551P4-921
NSN: 5305-00-151-8660
FSC: 5305 — Screws
CAGE: 58845 — ABOUNDING SECURITY INC DIV OF MAA CORP (USA)
SPECIFICATIONS
materialSTEEL COMP 4037 OVERALL
head_styleFLAT COUNTERSUNK
thread_class2A A
head_diameter0.357 INCHES NOMINAL IN
thread_length0.406 INCHES MINIMUM AND 0.436 INCHES MAXIMUM IN
shoulder_shapeROUND FIRST SHOULDER
fastener_length1.266 INCHES MINIMUM AND 1.296 INCHES MAXIMUM IN
shoulder_length0.796 INCHES MINIMUM AND 0.826 INCHES MAXIMUM FIRST SHOULDER IN
special_featuresHALF OF TOP SURFACE OF HEAD PAINTED ORANGE
thread_directionRIGHT-HAND
countersink_angle99.0 DEGREES MINIMUM AND 101.0 DEGREES NOMINAL
shoulder_diameter0.254 INCHES MINIMUM AND 0.256 INCHES MAXIMUM FIRST SHOULDER IN
NSN5305-00-151-8660
COMPONENT DIAGRAM
BOLT / SCREW — THREAD VERIFICATION REQUIRED Hex HEAD LENGTH: — THREAD: — × — MATERIAL: — PN: MA6551P4-921 · OEM ⚠ VERIFY BEFORE ORDERING Verify thread pitch before ordering — metric (M8×1.25) ≠ imperial (5/16-18). Wrong thread = wrong part. Grade/class stamped on bolt head determines tensile strength ✓ BROKER TIP Grade/class stamped on head determines tensile strength. Grade 8 > Grade 5 > Grade 2. Always confirm head marking matches specification requirement PARTSTABLE TECHNICAL DRAWING — NOT TO SCALE
KEY FEATURES
•
FASTENER LENGTH: 1.266 INCHES MINIMUM AND 1.296 INCHES MAXIMUM IN
•
SHOULDER LENGTH: 0.796 INCHES MINIMUM AND 0.826 INCHES MAXIMUM FIRST SHOULDER IN
•
SURFACE TREATMENT DOCUMENT AND CLASSIFICATION: QQ-P-416,TYPE 2,CLASS 3 FED SPEC SINGLE TREATMENT RESPONSE OVERALL
•
SHOULDER DIAMETER: 0.254 INCHES MINIMUM AND 0.256 INCHES MAXIMUM FIRST SHOULDER IN
•
THREAD LENGTH: 0.406 INCHES MINIMUM AND 0.436 INCHES MAXIMUM IN
•
SHOULDER SHAPE: ROUND FIRST SHOULDER
•
NOMINAL THREAD DIAMETER: 0.250 INCHES IN
•
HEAD STYLE: FLAT COUNTERSUNK
TECHNICAL CHARACTERISTICS
FASTENER LENGTH1.266 INCHES MINIMUM AND 1.296 INCHES MAXIMUM IN
SHOULDER LENGTH0.796 INCHES MINIMUM AND 0.826 INCHES MAXIMUM FIRST SHOULDER IN
SURFACE TREATMENT DOCUMENT AND CLASSIFICATIONQQ-P-416,TYPE 2,CLASS 3 FED SPEC SINGLE TREATMENT RESPONSE OVERALL
SHOULDER DIAMETER0.254 INCHES MINIMUM AND 0.256 INCHES MAXIMUM FIRST SHOULDER IN
THREAD LENGTH0.406 INCHES MINIMUM AND 0.436 INCHES MAXIMUM IN
SHOULDER SHAPEROUND FIRST SHOULDER
NOMINAL THREAD DIAMETER0.250 INCHES IN
HEAD STYLEFLAT COUNTERSUNK
THREAD DIRECTIONRIGHT-HAND
SPECIAL FEATURESHALF OF TOP SURFACE OF HEAD PAINTED ORANGE
OTHER ITEMS IN FSC 5305 — Screws
Items in the same Federal Supply class. No interchangeability or substitution relationship is implied.
5305-00-000-0094 5305-00-000-1397 5305-00-000-2625 5305-00-000-3669 5305-00-000-3830 5305-00-000-3831
SUBSTITUTES & CROSS-REFERENCES 5
BM19070-921Reference document
Same NSN cross-reference
Reference document — Advisory reference — outside the item-of-supply concept
GS551P4-921Reference document
Same NSN cross-reference
Reference document — Vendor item drawing reference
BM19070-4-921Reference document
Same NSN cross-reference
Reference document — Advisory reference — outside the item-of-supply concept
2R1465-13Reference document
Same NSN cross-reference
Reference document — Secondary reference
2R1863-921Reference document
Same NSN cross-reference
Reference document — Secondary reference
LIFECYCLE
NSN statusActive· U.S. Government catalog
Acquisition advice: Normally procured from the manufacturer (OEM)No demilitarization required
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FREQUENTLY ASKED QUESTIONS
What is MA6551P4-921?
MA6551P4-921 is a SCREW,SHOULDER.
What parts can replace MA6551P4-921?
There are 5 known substitutes for MA6551P4-921: BM19070-921, GS551P4-921, BM19070-4-921 and 2 more. Substitute compatibility should be verified for your specific system.
What is the NSN for MA6551P4-921?
MA6551P4-921 is cataloged in the U.S. Government catalog under NSN 5305-00-151-8660. This indicates validated use in U.S. government and defense supply chains.
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✓ PartsTable — the parts reference. Every fact cited to its source.
PartsTable Design LLC · partstable.com
U.S. Government catalog: edition PUBLOGDVD v12.0.0 (OCT 2026), edition date 2026-10-01, retrieved 2026-10-18.
PartsTable commercial catalog: edition Unified commercial catalog snapshot through 2026-09-28, edition date not on file, retrieved 2026-09-28.