USMC Infantry MOS 0311 Combat Ready T-Shirt. Digitally Printed on soft superior 100% ring-spun Cotton, Triblend, 50/50 premium Soft Style Quality T-shirts. Not Slim Fit Size XXL is Heavy Cotton. The basic infantry weapon of the United States Marine Corps is the M4 Carbine. The M27 Infantry Automatic Rifle (IAR) is a lightweight, magazine-fed 5.56mm, select-fire weapon. It is used by the United States Marine Corps and is intended to enhance an automatic rifleman's maneuverability. The design contains an Infantryman's assault Rifle, United States Marines Est 1775, 0311 Dealers in Death followed by Semper Fi Do or Die. The front of the design is the U.S. Flag with "Defend at All Cost". The artwork behind the model is a clear example of the quality of the design printed on the shirt.