Bore Tech Chamber Brush Nylon Brushes 7.62mm 308 Cal Rifle 8-32 Aluminum/Nylon 3" Nylon Brush Bore Techs Proof-Positive Nylon Chamber Brushes Were Specifically Designed To effectively remove The Stubborn Carbon Fouling Found In AR-15/AR-10 Chambers And Barrel extensions. With Twice The Amount Of Oversized bristles, Double Wound cores, looped ends And Barrel Safe studs These Brushes Are exceptionally ridged And Provide Safe And Effective Scrubbing Action. Bristle Type: Nylon Length: 3" Material: Aluminum/Nylon Thread Pattern: 8-32