Match-Grade - Superb Accuracy (2" Or Less At 25 Yards With Good Ammo); 1 in 16" Twist; Fully Machined From Aircraft Grade Stainless Steel Forgings; Heat-Treated To R/C 40 For Maximum Service Life; Critical Manufacturing Tolerances Are Held To Less Than .0005" (One Half Thousandth Of An Inch!); Glass Smooth Chamber And Perfectly Concentric With The Bore; In the Barrel Test Fixture We Routinely Obtain 1/2" At 25 Yard Groups; Detailed Final Inspection Prior To Receiving The Wilson Name On The Hood; Critical Lock-Up Contact Areas Cut To A Dimension That Provides A Good Lock-Up In Most Colt And Springfield Armory Pistols; Includes Barrel Bushing