A breech load pistol conversion kit which may be adapted to the frame of a semi-automatic pistol. A modified slide is slidably mounted to the pistol frame and is adapted to include a pivotal barrel. A lever actuated breech release mechanism is also provided for unlocking and allowing the barrel to pivot. The present invention relates to a safety interface member slidably disposed with respect to the slide and the pistol frame. The member engages and disengages a disconnector in the frame to provide a safety against hammer release when the pistol the breech release mechanism is activated and the pistol is not in a firing position.