Hey, so despite my love for them, I'm relatively new to

>>34174986
In most semi-automatic handguns, the follower of the magazine engages with part of the slide release. The slide release is normally being acted on by a spring to prevent the slide from being locked to the rear no matter the position of the handgun, be it upright or inverted. When the follower engages with the slide release after the last round has been chambered, the force of the magazine spring, which is greater than that exerted by the slide release spring, is overcome and part of the slide release now has a net upwards force being applied to it. Once the last round is fired and the slide is cycled to the rear, this net force causes the slide release to move up and engage with a cutout in the slide.

There's a tab on the magazine follower that presses up against the inside of the slide catch/release. This tab is usually a small pad on the front left of the follower and works through spring tension. The space it occupies is largely empty until the mag empties due to the stacking of the ammunition being sorted out of the way by the mag body. When you lock back the slide with an empty mag installed you should be able to see what's going on inside the ejection port.