Abstract: A one-piece dart comprising a shaft having an integral suction cup at its forward end and an integral, air actuable, propelling element at its rearward end, the dart being molded from a soft, flexible plastic material. A spring activated air operated dart gun including a dart barrel having a non-circular cross section uniform throughout the length of the barrel, the propelling element on the dart being complementary to the dart barrel so that the propelling element makes a substantially air tight seal with the dart barrel. A dart barrel and a dart propelling element which are substantially square. An air operated dart gun having a barrier for positively preventing physical contact between an air displacing piston and the dart, and for making physical contact between the piston and a foreign object in the dart barrel virtually impossible. A piston provided with a central conical element facing the dart barrel.