What Makes these Barrels Special and Precise: Certified US 416R Rifle Grade Stainless Steel Precision CNC machining Hand-honed Bores Twist rate 9mm, 38 super, 380 Auto, 357Sig, 9x23, 9x25 Dillon, = 1:10 Twist rate 45acp, 40S&W/10mm = 1:16 Match grade Precision button rifling Air-gaged bores and rifling Accu-bored Chambers and Hand honed Simple fitting points on the back of the hood and barrel foot (will drop in tightly in many productions manufactured 1911’s) Available in bull and standard bushing barrel configurations Available in standard Mil style, Wilson/Nowlin, and Para/Clark Ramp configurations Full .055 top locking Lug cut dimensions Fully and Completely MADE IN THE USA