United States Marine Corps Machine Gunner MOS 0331 Semper Fidelis T-Shirt. Digitally Printed on soft superior 100% Cotton, Triblend, 50/50 premium Soft Style Quality T-shirts. Not Slim Fit Size XXL is Heavy Cotton. Machine gunners first must attend basic training and become a U.S. Marine Corps infantry rifleman. Following basic training in either Parris Island, N.C. or San Diego Marine Corps Recruit Depot in California, machine gunners attend the Machine Gunner Course at the School of Infantry at Camp Lejeune in North Carolina or at Camp Pendleton in California. The design consists of two crossed machine Guns with the title USMC, est 1775, Semper Fidelis.