Another common inspection point is the straightness of a bolt or screw. The distinction between a bolt and a screw is commonly misunderstood. This distinction is consistent with ASME B18.2.1 and some dictionary definitions for "screw" and "bolt". The M2 fires from a closed bolt, operated on the short recoil principle. The RPD is hammer fired from an open bolt. This prompted Dillon to improve other design aspects including the bolt, housing and barrel. Other minor modifications were made to the bolt and carrier assembly. All SaskSten guns fire from an open bolt. The weapon fires from an open bolt. The MAG fires from an open bolt. Storm later kills her with a lightning bolt. The safety, bolt, and trigger were completely redesigned. These were rates that contemporary bolt action rifles could not match. The F2000 is a selective fire weapon operating from a closed bolt. Their logo has been a stylized lightning bolt.