JP Enterprises Supermatch Barrel With Headspaced Jp Enhanced Bolt 18in Light Contour Black. 5" Supermatch Barrel Light Contour 416R Ss 8 Twist Button Rifled Hand Lapped Cryogenically Treated Mid-Length Gas Port Position 1/2-28Tpi Machined Stainless Finished Exterior. Specifications for JP Enterprises Supermatch Barrel With Headspaced Jp Enhanced Bolt: Manufacturer: JP Enterprises Caliber: .223 Wylde Condition: New Features of JP Enterprises Supermatch Barrel With Headspaced Jp Enhanced Bolt Option: JP Thermal dissipator size (Heat Sink) selection guide: This barrel takes our short .650 OD Thermal Dissipator (JPTD650S). Package Contents: JP Enterprises Supermatch Barrel With Headspaced Jp Enhanced Bolt JP Enterprises JPSM223-18L8R-BT: Supermatch Barrel With Headspaced Jp Enhanced Bolt 18in Light Contour Black