A locking block device (100) provided in the region of a cartridge chamber (121) of a handgun barrel (120) has a locking block (110) for releasably locking the barrel (120) to a breech prior to firing, and has a control member (111) having a control guide (112) for swinging out the barrel (120), after firing, for the purpose of separating the barrel (120) from the breech, and further has a feed ramp (140) formed in the region of a stop member (130) of the locking block (110) for feeding a cartridge, stored in a magazine of the handgun, into the cartridge chamber (121) following ejection of a fired cartridge. A modular design capable of being adapted to meet specific requirements is achieved in that the feed ramp (140) is formed on a ramp member (150) capable of being separated from the locking block (110) and releasably locked to the locking block (110).