Proof Research Terminus Zeus 223 Remington Threaded Rifle Barrel Competition 26 in 7 Twist Pxt 5/8-24 Thread 7.5 Weight Silver. PXT - PROOF Exponential Twist - is a complete rethinking of conventional rifling geometry and twist progression engineered to reduce engraving force minimize throat erosion and create a smoother transition as the projectile engages the rifling. Specifications for Proof Research Terminus Zeus 223 Remington Threaded Rifle Barrel: Manufacturer: Proof Research Color: Silver Caliber: .223 Remington Projectile Caliber: .224 Caliber Barrel Length: 26 in Barrel Material: Stainless Steel Barrel Profile: Competition Firearms Threads Per Inch: 5/8x24 Gun Make: Terminus Gun Model: Terminus Zeus Weight: 7.5 lb Gun Type: Rifle Package Contents: Proof Research Terminus Zeus 223Rem Threaded Rifle Barrel What firearm models does the manufacturer say Proof Research Terminus Zeus 223 Remington Threaded Rifle Barrel is compatible with? The manufacturer says that Proof Research Terminus Zeus 223 Remington Threaded Rifle Barrel is compatible with Terminus ZeusProof Research 155769: Terminus Zeus 223 Remington Threaded Rifle Barrel Competition 26 in 7 Twist Pxt 5/8-24 Thread 7.5 Weight Silver