kinematics - How can a horizontally fired bullet reach the ground the same time a dropped bullet does?

I studied projectile motion and now I know that we can treat each component of motion independently. Since gravitational acceleration acts on both a horizontally launched bullet and a vertically dropped bullet in free fall, they both will reach the ground at the same time as their vertical initial velocity is zero. This is what I studied in high school. But I found it against a real observation that a horizontally fired bullet will travel for much longer time compared to a simply dropped bullet before hitting the ground. Could you please elaborate on how to connect the physics of the situation and real life observations?