Interesting fact from 1940's Western Ammunition Handbook


#1

I found the following statement in a late 30’s Western Ammunition Handbook. I’m not sure how they proved this??

A Bullet Dropped and One Fired From Rifle
Hit the Ground at the Same Instant

 It is hard to believe, but true. Two bullets, one fired from a rifle placed exactly parallel to the ground, and one dropped from a point exactly the same distance above the ground as the rifle barrel, will strike the ground at the same instant.

 The pull of gravity on both bullets is exactly the same. Of course, the bullets must be of the same size, shape and weight---there should be no wind, or practically none---and the ground at the tow points where the bullets hit would have to be at exactly the same level.

#2

Just basic physics. A variant of this was proven during one of the moon missions. A falcon feather and a hammer were both dropped from the same height at the same time. They landed on the surface simultaneously.


#3

Neat, eh? Even with large caliber guns it works!


#4

I’m not sure that the hammer and feature drop would wok out the same in the Earth’s atmosphere unless they could find a very large feather and a miniature hammer that weighed the same…


#5

correct. that was the point of the exercise, to prove that mass of the object does not affect how fast it falls, something that you couldn’t demonstrate very well inside an atmosphere.


#6

A couple of years ago the Mythbusters show did a segment proving this was true. If I remember correctly they used a .45 ACP. The most difficult part was synchronizing the firing of the pistol and the release of the plain bullet simultaneously.


#7

Seems like knowing exactly “where” and when the fired bullet would drop would be awfully difficult to prove and photograph also. I think even small differences in the powder loads from one round to the next would change where the bullet would touch down. Even saying that the fired round and the dropped round touched earth at the same time, more or less powder could mean faster or slower speed resulting in a closer or farther away touchdown?? Just wondering…


#8

As Keith said, it’s simple physics. IOW, one of Mother Nature’s laws. Can’t be bent or broken. As unbelievable as some of her laws seem to us, you just have to believe.

Velocity of the bullet will only change the distance it travels before touching down, not the time it takes to do so.

Ray


#9

Ray, that is what I was trying to say. Fluctuation in powder charges will change “where” it will strike the earth but not when. Knowing exactly “where” it would land could prove difficult to a film crew that was trying to prove/disprove the theory.


#10

Roger–Mythbusters started out by firing about 10 rounds from a pistol held in a Ransom Rest at about 5 feet above the ground. They were shooting down an airport runway. They found that for a given lot of ammunition the impact point on the runway was something like +/- 2 or 3 feet. Once that point was found they set up a high speed camera to film both the fired and dropped bullets together. As I recall they measured the time to 10,000 of a second. And, of course, as Mother Nature has said, they both impacted the ground EXACTLY the same time.


#11

Roger–Google “Mythbusters Bullet Drop” and you will find a whole series of videos on how they did this test.


#12

Mythbusters makes for an interesting TV show. I watch it from time to time. But, most of the “myths” that they “bust” are not really myths at all. They could have proven the bullet drop theory with a simple physics formula, but that would not have made for much of a show. I often wonder, how much film footage do they have of failed experiments where they were unable to bust the myth?

Ray


#13

… Unless it’s a Gyrojet, which is sort of cheating.


#14

Why would the pull of gravity be different on a gyrojet?


#15

Gravity effect certainly doesn’t change, but the acceleration of the gyrojet continues once the projectile leaves the barrel. The moment the conventional projectile leaves it is decelerating.?


#16

But, that only means that the gyrojet may travel further before it touches down. And even that may or may not be true. Remember, it starts out at a velocity much lower than a bullet fired conventionally. So, for the time that it takes for gravity to do its job, the distance travelled may or may not be the same. It depends on the velocity of whatever bullet it’s being compared with. The time does not change, only the distance.

Am I missing something?


#17

Ray - As the Forum’s chief moron, I should not be even sticking my nose in here. I am probably way out in left field.

Since the rocket action of the fueled projectile continues to propel it in flight long, thereby defeating gravity just an airplane with fuel left continues on its way in flight,
would that not affect its time in flight compared to an inert projectile that has been propelled only by the amount of gas acting on it within the confines of its pressure vessal, the gun’s barrel and bore?

I am thinking that if you carried an unfueled jet plane up to one thousand feet attached to the belly of another plane that was fueled for normal flying, and dropped it, that it would hit the ground while the fueled, piloted aircraft would continue, through its aerodynamics, in flight for as long as the pilot wished and the plane had fuel. That could be hours after the “inert” aricraft had hit the ground. Wouldn’t the instance of a gyroject rocket projectile in flight be the same? That is, travel until it ran out of fuel and inertia and gravity took over.

Probably a totally hare-brained though on my part. I have little background in simple math and none in physics.

edited only for typo errors


#18

I was thinking along those same lines as John but was afraid to express it for fear of showing how stupid I am…


#19

An airplane, of course, resists the pull of gravity because of aerodynamic lift. A bullet, gyrojet, or a rock, do not have aerodynamics to keep them aloft. They do not defeat gravity. The time that it takes gravity to pull them to earth is the same.

Unless I am incorrect in my understanding of how gyrojets work. I believe they are stabilized by spinning, the same as a bullet. The difference is that a bullet is spun by the rifleing in the barrel, whereas a gyrojet is spun by the ports in its base. Even a gyrojet weapon has to be pointed or aimed at an angle to achieve any distance. IOW, it has a trajectory the same as a conventional bullet, or a thrown rock, for that matter. If they did not, they would indeed be defying Mother Nature and would have replaced bullets fired from rifled barrels a long time ago.

Ray


#20

If you really want to get into one of the more confusing aspects of ballistics, especially on this Christmas day, consider the velocity and trajectory of a bullet fired from the tail of a fast flying aircraft vs the same fired from the nose.

Ray