From Mossberg . . .
At the core of the 940 Pro platform is a durable gas system that can run up to 1,500 rounds before cleaning and is compatible with factory-manufactured 2.75 or 3-inch shells. Performance-driven features include oversized, beveled loading port with redesigned elevator and shell catch to allow for efficient and pinch-free loading into the magazine tube; new barrel-making process to maintain point-of-aim and impact; slim-profile forend and user-configurable stock for length-of-pull (13 – 14.25 inches), drop, and cast; and oversized charging handle and bolt release button for ease of operation.