Magazine safety units for a self-loading firearm

For use with a firearm having a grip, a sliding support, a magazine shaft, a trigger, a hammer, and a removable magazine, a magazine safety unit comprising:

• a bar to operatively connect the trigger and the hammer;
• a lever mounted for pivoting movement about a pivot pin;
• and
• a spring biasing the lever into engagement with the bar such that, when the lever engages the bar, the bar is prevented from moving in a first direction, the lever being positioned such that, insertion of the magazine into the firearm pivots the lever against a biasing force of the spring and out of engagement with the bar,
• wherein when the lever is not engaged by the magazine, the sliding support is movable in a second direction, and the sliding support pivots the lever when the sliding support moves in the second direction, such that the lever disengages the bar, so that, despite the magazine being removed from the firearm, the hammer can be moved.