Gun shot in the air

[dansillysod]

how far would a bullet go if a gun was fired in the air? and if it came bakck down could it penetrate a human skull?

[brachiopod]

Depends what angle you fire it - commonly called the angle of trajectory.

If fired directly up into the air, perfectlly vertically, it will, of course, reach a maximum height. This will depend on the muzzle velocity of the bullet.

On the way down, the bullet's velocity starts at zero (as it reaches it's maximum height and starts falling back to Earth under its own weight), as apposed to the thousands of feet per second (or whatever) as it leaves a rifle barrel. On it's fall back to earth, it will reach a terminal velocity no matter how high it falls from, which is a lot lower than typical rifle velocities - again, depending on the type, shape and mass of the bullet

[Clanad]

To pedantically supplement brachiopod's answer: the publication Wound Ballistics Review speaks of a study by Julian Hatcher that explained: Hatcher's tests indicated that on the average, vertically fired rifle bullets reach about 9000 feet in altitude (slowed from their muzzle velocity by air drag and gravity to zero velocity), taking about 20 seconds to reach maximum height. Then, pulled by gravity, and slowed by air drag they take about 40 or so seconds to return. Bullets fired vertically come back base first. Hatcher describes one experiment with the 150gr M2 Ball bullet fired vertically. When it came back from vertical (round trip time was about 42.9 seconds) it left only a 1/16 inch dent in a soft pine board that it happened to hit. Based upon this and similar tests Hatcher concluded that the impact velocity was about 300 f/s, which from additional testing appears to be the terminal velocity, compared to 2,700 f/s when fired...

[Golem]

The Straight Dope attempted to answer this question and quotes the same research as Clanard, but provides some contrary findings:

http://www.straightdope.com/classics/a950414b.html

[4getmenot]

You havent by any chance watched Jarhead have you??

[sddsddean]

Many years ago (well about 23) when I was at Uni I was in the rifle club and took a course to train as a small bore (.22) coach. One of the lecturers there told us about a guy in Sutton Park in Birmingham who was having a picnic with his family when he suddenly slumped forward... apparently dead. At the PM they found a .22 bullet in the back of his neck. The Police eventually traced a guy who had been shooting pigeons about 3/4 mile away as the culprit. He had never thought about what happened to the the shots that missed the pigeons. So it does happen (or at least has happened once).