Introducing the Dirty Bird Industries 9mm Bolt Carrier. Made out of 8620 Steel, and designed to work with Colt and Glock style magazines, this BCG is designed to make sure that you will not have any malfunctions when you are out in the field or on the range. We then had these coated in a smooth black nitride coating to reduce the chance of corrosion and have a slick-looking BCG. We also wanted to make sure that we could have a removable counterweight with our 9mm BCG to accommodate for ever popular Silent Recoil Systems in the industry.