This 4th generation model has all the features of the previous models. You can Lock the magazine in a fixed position for top loading. Drop the magazine with a tool inserted into the Bullet Button® Convertible. Drop the magazine by pushing on the Bullet Button® Convertible itself.

All you need is to turn the set screw the approprate amount of turns for each setting. Each setting has its advantages and legalities. (with setting 3 being for use outside of California).