Unchambered 458 Caliber, 1-14" Twist, 26" Length, Custom Contouring: Breach Diameter (A)= 1.225 for 2.75"(B), (C)= 2.500",(D)=.750" Muzzle diameter, No threading or crowning. Polished Chromoly Blank in the white If you would like additional work done for this barrel, give us a call!