Proof Research Terminus Zeus 6 Dasher Threaded Rifle Barrel Competition 26 in 7.5 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 6 Dasher Threaded Rifle Barrel: Manufacturer: Proof Research Color: Silver Caliber: 6mm Dasher Projectile Caliber: .243 Caliber Barrel Length: 26 in Barrel Material: Stainless Steel Barrel Twist Rate: 1-7.5 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 6 Dasher Threaded Rifle Barrel What firearm models does the manufacturer say Proof Research Terminus Zeus 6 Dasher Threaded Rifle Barrel is compatible with? The manufacturer says that Proof Research Terminus Zeus 6 Dasher Threaded Rifle Barrel is compatible with Terminus ZeusProof Research 155820: Terminus Zeus 6 Dasher Threaded Rifle Barrel Competition 26 in 7.5 Twist Pxt 5/8-24 Thread 7.5 Weight Silver