A pistol has a trigger 18 pivotal between a forward rest and a rearward depressed condition. It has a firing pin assembly 60 incorporating a firing pin 68 and a transverse nose 74. The assembly 60 is translational parallel to a barrel. When in rearward, cocked condition as illustrated, a firing pin 76 is compressed to propel it forward when released. A transmission member 50 is pivoted at a fore end to the trigger 18 and is guided for displacement along a cocking path. The nose 74 extends into the cocking path. Depression of the trigger displaces the member 50 along the cocking path. The member 50 abuts the nose 74 and cocks the assembly 60. The invention provides a pivot member 64 which hooks onto the member 50 and deflects it out of its cocking path to release the nose when the assembly 60 is cocked. A resetting formation 96 is provided on a movable slide 14 to reverse pivot the pivot member 64 to disengage it from the member 50 when a cartridge has been fired.