WMD Guns AR-15 Threaded Stripped Upper Receiver Forged NiB-X Silver. Ideal building block for a long lasting AR15. This 7075 T6 Aluminum forged Mil Spec stripped receiver with M4 feed ramps has NiB-X coating inside and out to provide an exceptionally tough ultra-smooth surface finish for outstanding wear resistance and lubricity. Specifications for WMD Guns AR-15 Threaded Stripped Upper Receiver Forged: Manufacturer: WMD Guns Color: Silver Finish: NiB-X Fabric/Material: 7075-T6 Aluminum Caliber: 5.56x45mm NATO Gun Make: AR Platform Gun Model: AR-15 Package Contents: WMD Guns AR-15 Threaded Stripped Upper Receiver Forged What firearm models does the manufacturer say WMD Guns AR-15 Threaded Stripped Upper Receiver Forged is compatible with? The manufacturer says that WMD Guns AR-15 Threaded Stripped Upper Receiver Forged is compatible with AR-15WMD Guns 1-NIBXURF: AR-15 Threaded Stripped Upper Receiver Forged NiB-X Silver