Precision Reflex AR15/M16 Replacement Barrel Nut Steel Black. Id of barrel nut is 1.02. Designed for a Standard AR15 Wrench or a wrench designed for 20 hole pattern on a 1.56 bolt hole pattern. Specifications for Precision Reflex AR15/M16 Replacement Barrel Nuts: Manufacturer: Precision Reflex Color: Black Gun Model: AR-15 Package Contents: Precision Reflex AR15/M16 Replacement Barrel Nuts What firearm models does the manufacturer say Precision Reflex AR15/M16 Replacement Barrel Nuts is compatible with? The manufacturer suggests that Precision Reflex AR15/M16 Replacement Barrel Nuts is compatible with AR-15Precision Reflex 05-074-01: AR15/M16 Replacement Barrel Nut Steel Black