[Reading Science] If You Shoot a Gun Toward the Sky, What Happens to the Bullet?

What happens to a bullet when you shoot a gun vertically into the sky?
[Photo by YouTube screen capture]

[Asia Economy Reporter Kim Jonghwa] One common scene in movies is shooting a gun into the sky. It may be to attract attention in a noisy and chaotic situation, to celebrate something, or to ignite fighting spirit.

This scene is also easily witnessed in some countries where gun use is permitted or where "Celebratory gunfire" is customary. However, the point to note is the material of the bullets fired into the sky. Movies usually only show the act of shooting, and do not kindly satisfy the audience's curiosity about what happens to the bullets afterward.

Where do bullets fired into the sky go? They do not keep rising endlessly. Once all the energy from firing is exhausted, that is, as gravity and friction gradually reduce the speed until it stops, the bullet falls back to the ground due to gravity. Unless it hits a flying plane or bird, the bullet will fall back to the ground under gravity.

The problem is that when these bullets fall back, they accelerate and fall toward the ground at tremendous speeds. It is also impossible to predict exactly where they will land. Even if the gun is fired vertically, the spinning bullet can curve due to air resistance, and the wind can change its direction, making the impact point unpredictable.

How high can a bullet rise? When fired horizontally, air resistance rapidly decelerates the bullet. Typically, a rifle bullet reaches about 500 meters, dropping to about half its initial speed, and then quickly falls to the ground due to gravity. When fired vertically, the bullet continues to rise until its speed reaches zero; some rifles can reach up to 3 kilometers in height.

In 1947, U.S. Army Major Julian Hatcher published experimental results on how far bullets fired from various firearms could travel. The M1 Garand rifle, the main rifle of the U.S. Army at the time, reached 2,740 meters in 18 seconds, then fell freely for 31 seconds at an average speed of 90 meters per second.

Dr. James Walker of the Southwest Research Institute recently reported that the bullet's maximum altitude is greatly affected by the type of weapon and ammunition used. Also, the final falling speed varies depending on the firing angle; if fired perfectly vertically, the final falling speed decreases, but if fired in a parabolic arc, the falling speed increases. So, how fast do bullets fall during free fall?

To calculate the falling speed of a bullet, you need to know its weight. For the well-known M16 rifle, the bullet weighs about 4 grams. Assuming an average range of 1 km for various firearms (the M16's maximum range is 2,653 meters), the falling speed of the bullet is about 140 meters per second.

This speed is not maintained continuously. When falling, once a certain speed is reached where gravity and air resistance balance, acceleration ceases and the bullet moves at a constant speed, called terminal velocity. Terminal velocity is the maximum speed an object can reach while falling through a fluid.

The terminal velocity of an M16 bullet is about 45 meters per second. The actual power of a firearm comes from the bullet's spin, but a bullet falling from the sky can be considered a 4-gram weight. What happens if a person is hit by a 4-gram iron weight falling at 45 meters per second? At speeds above 45 m/s, it can penetrate human skin, and at speeds above 60 m/s, it can penetrate the skull.

Depending on the firing angle, a 4-gram bullet can reach a falling speed of up to 180 meters per second. If a person is hit, there is a high possibility of serious injury or death. The impact is comparable to a brick falling from a high-rise building.

Guests attending a wedding in an Arab country are firing guns into the air as a form of celebration. This practice has caused many injuries and fatalities.
[Photo by YouTube screen capture]

There are quite a few cases of people being injured or killed by bullets fired into the sky. In 2012, in Saudi Arabia, bullets fired to celebrate a wedding cut power lines, electrocuting 23 people. In 2005, during New Year's celebrations in Macedonia, a girl walking by was hit and killed by a stray bullet. In 2003, wedding celebratory gunfire in Serbia hit an airplane.

In 2010, in Jordan, after a graduation exam similar to Korea's college entrance exam, a shooting incident during the celebration resulted in 2 deaths and 13 injuries. In 2017, a Texas state representative in the U.S. suffered a bullet lodged in his skull, and in the same year, a teenager was seriously injured by a bullet fired into the sky during Independence Day celebrations.

Such accidents frequently occur in countries like Afghanistan, Pakistan, India, and Paraguay. In densely populated urban areas, firing guns into the sky increases the likelihood of people being hit by falling bullets. Some U.S. states, troubled by gun accidents, strictly regulate firing guns into the sky.

In the distant future, Korea might become a country where gun use is permitted. Even if that day comes, firing guns into the sky should be avoided. No matter what, innocent victims must not occur.