Alpha Shooting Sports CHF 5.56 NATO Mid Spiral Fluted Barrel 16in Stainless ALP16-556SSSFCH. Specifications for Alpha Shooting Sports CHF 5.56 NATO Mid Spiral Fluted Barrel: Manufacturer: Alpha Shooting Sports Caliber: 5.56x45mm NATO Barrel Length: 16 in Gas System Length: Mid Length Threads per Inch: 1/2x28 Barrel Twist Rate: 1-8 Flutes: Spiral Weight: 1.9 lb Features of CHF 5.56 NATO Mid Spiral Fluted Barrel: 16" in length and chambered in 5.56 NATO with a 1 to 8 twist. Mid length gas port location. Machined in house from a premium cold hammer forged 416R stainless blank. Spiral fluted to increase surface area for better cooling and weight reduction. Extended M4 feed ramps. 100percent made in specialized factories. Package Contents: Alpha Shooting Sports CHF 5.56 NATO Mid Spiral Fluted Barrel Alpha Shooting Sports ALP16_556SSSFCH: CHF 5.56 NATO Mid Spiral Fluted Barrel Stainless 16in