USMC MOS 0311 Infantryman and US Army MOS 11 Bravo Infantry Grenade Launcher Graphic 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. A grenade launcher is a weapon that fires a specially-designed large-caliber projectile, often with an explosive, smoke or gas warhead. Today, the term generally refers to a class of dedicated firearms firing unitary grenade cartridges. The most common type are man-portable, shoulder-fired weapons issued to individuals, although larger crew-served launchers are issued at higher levels of organisation by military forces. The design consists of a M203 Grenade Launcher Weapons System.