Rainier Arms Mountain MOD3 Series 5.56 NATO AR-15 Threaded Barrel 10.5 inch Carbine Length 1-8 Twist 1/2x28 Black Medium. While these barrels will not reject heat in the same way our fluted Mountain barrels well they're still going to be excellent options for the budget minded shooter looking for a more general purpose barrel. Our Craftsmanship Rainier barrels are meticulously designed and machined by precision gunsmiths. Our barrels are turned the same way true artisans have made premium rifle barrels for over a century. Each barrel has hand-cut chambers and crowns with the attention to detail that can only come from highly trained human intervention. While most companies strive for faster production time to cut costs we strive for perfection. There are no shortcuts with our barrels period. We will go toe to toe with anyone and win. Specifications for Rainier Arms Mountain MOD3 Series 5.56 NATO AR-15 Threaded Barrel: Manufacturer: Rainier Arms Color: Black Fabric/Material: Stainless Steel Caliber: 5.56x45mm NATO Gas System Length: Carbine Length Gas Block Journal Size-Diameter: .750 in Threads per Inch: 1/2x28 Barrel Material: Stainless Steel Flutes: No Gun Make: AR Platform Gun Model: AR-15 Package Contents: Rainier Arms Mountain MOD3 Series 5.56 NATO AR-15 Threaded Barrel What firearm models does the manufacturer say Rainier Arms Mountain MOD3 Series 5.56 NATO AR-15 Threaded Barrel is compatible with? The manufacturer says that Rainier Arms Mountain MOD3 Series 5.56 NATO AR-15 Threaded Barrel is compatible with AR-15Rainier Arms RAB-CMV-556-105-C-NF-BLK: Mountain MOD3 Series 5.56 NATO AR-15 Threaded Barrel 10.5 inch Carbine Length 1-8 Twist 1/2x28 Black Medium