Black Washers - 7/16 ID x .660 OD (10)

The Black Washers - 7/16 ID x .660 OD (10) from ARP are precision fastener components engineered for critical assembly applications in tactical firearms, armor systems, and high-performance equipment builds. These hardened steel washers distribute load across bolt and screw connections, preventing surface damage and fastener pull-through on both soft and hard materials. Whether you're assembling custom upper receivers, mounting optics, installing rail systems, or maintaining duty-grade firearms, quality washers are non-negotiable—cheap fastener failures in the field create liability and downtime.

Each washer features a 7/16-inch inner diameter (ID) and .660-inch outer diameter (OD), providing optimal bearing surface for standard 7/16" fasteners while maintaining compact profile suitable for crowded assembly areas. The black oxide or phosphate finish resists corrosion and conceals light reflection, critical for tactical applications requiring low visibility. ARP's manufacturing standards ensure uniform thickness and hardness across all ten pieces, eliminating the inconsistency found in surplus or budget alternatives. The minimal 0.08 lb total weight per set reflects the efficiency of the design—no unnecessary mass, only functional material where stress concentration occurs.

Armorers, gunsmiths, and tactical equipment builders rely on ARP washers for any application requiring repeatable, mil-spec compatible fastening. Ten-piece packs provide sufficient quantity for multi-component builds or replacement stock on your bench. Use these washers under bolt heads or screw heads wherever you need to increase bearing surface area, reduce vibration loosening, or prevent damage to precision-machined surfaces—from lower receiver assembly to accessory mounting. Compatible with all standard 7/16" hardware across AR platforms, shotguns, precision rifles, and modular armor systems.