The Complete MARCK-15-SMG-9C Weapon System. This configuration of the Hydra is set up for 9mm that utilizes Colt Style 9mm SMG magazines . It includes the Modular Lower Receiver with a 9mm SMG Magazine-Well, the QCB-D Upper Receiver and a 16-inch blow back barrel and a 9mm blow back bolt. With this base system, you can purchase and utilize the rest of ever-growing system including our various magazine wells and caliber conversions. To convert this system to another caliber, you will need to change the barrel, bolt, bolt carrier and magazine well to the desired caliber. With caliber conversions already available, and many more coming into production, this weapon system continues to grow and become the most versatile Black Rifle platform the industry has ever seen. FFL necessary to purchase. All Federal and State Rules apply. California Residents are required to select the California bullet button option.