KKM Precision Stainless Steel Match Grade Barrels are machined from 416 stainless steel on state of the art computer controlled CNC machines and are hardened to a 42 Rockwell. These stainless steel masterpieces of machining & hand finishing are intended for the competition shooter - or even the serious shooter - who wants the ultimate in performance and quality. This Match Grade barrel will help most shooters produce better groupings, due to the tight tolerances incorporated into its design. The fit and finish of this barrel are top quality - it offers a tight lock-up and the highest accuracy attainable. We have tested these barrels for fit and function - we are convinced that KKM is one of the top producers of premium Glock barrels. *The .40 to 9mm conversion barrels were specially developed to shoot 9mm ammunition. These barrels are intended for training purposes. We suggest changing the ejector and extractor on the gun for proper ejection.