The outstanding characteristic of the revolver is the multichambered cylinder which feeds into a single barrel. Almost all revolvers are built with both single and double actions, the former for accuracy and the latter for rapid fire. The frame of the revolver comprises the metal part of the grip and that part which accommodates the cylinder and lock work. Remaining components include the barrel, cylinder, and grips. The two types of frames which are commonly used are the break action and the solid frame with swing-out cylinder. Revolvers are rarely fitted with safety catches because there is no need to carry them cocked, and the 14-pound double action pull is reasonably safe from accidental discharge. The diameter of the chamber is reduced immediately in front of the cartridge case to allow a small clearance for the bullet, but only the barrel is rifled. Common foresights of revolvers include the barleycorn, the blade, and the blade on ramp. The solid frame, swing-out cylinder revolver is now used exclusively in the United States for military and civilian police forces. Three sketches are provided.