Height

Falling three feetThis is a common question in elementary physics and the wrong answer (that the bullets will land at the same time) is given quite frequently. Though some would argue that factoring in lift due to exceeding terminal velocity is excessive and needlessly complicates things to make a point that changes the answer only slightly, the truth of the matter is that the fired bullet will take almost twice as long to land.

Although you didn't state it explicitly in your question, we will assume the bullet fired from the rifle starts out three feet off the ground, not at shoulder height.

Assuming that, the bullets will strike the ground at nearly the same time!! For many people that is a counter-intuitive answer.

Orthogonal forces -- that is, forces at right angles to each other -- have no effect on each other. When a bullet is fired from a gun, the force due to gravity works at right angles to the bullet's horizontal motion. The bullet's horizontal motion and any forces acting on the bullet in the horizontal direction have no effect on the motion of, or the forces acting on, the bullet in the vertical direction.

When the bullet leaves the end of the muzzle of the gun, gravitational forces will start to act on the bullet immediately. The bullet will accelerate toward the ground at 9.8 meters per second squared (32.2 feet per second squared), just like any object that is dropped and falling freely.

At this point you might think they would strike the ground simultaneously. However, drag forces caused by the bullet exceeding terminal velocity would cause a lift. Similar to the principle upon which plane flight is based. This would cause the fired bullet to stay airborne slightly longer than the dropped bullet.

The dropped bullet will strike the ground in about 432 milliseconds (0.432 second).

The fired bullet will land shortly after.

(Except the bullet would go far beyond an empty football field, unless it hit a wall at the end of it or something...)