Do heavier bullets drop faster than lighter bullets....

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Drop is based on velocity, velocity over the length of the distance traveled. Since both bullets will have similar effects from gravity, the one that is traveling faster for the length of travel will have spent fewer milliseconds subject to gravity. Yet heavy bullets often due that better than the lightest loads.

The bullet is slowed by air resistance. The more surface area, and the shape of the projectile relative to its total mass determine how much it is effected.

Heavier bullets actualy tend to have more forward moving mass for a given surface area ratio. So even though thier initial velocity will be lower in the same loading, thier overall bullet drop over distance is less because at range they are going faster.

This is all factored into the ballistic coeffecient.
The ballistic coeffecient combined with initial velocity will tell you just how much drop you will have over distance.
Heavier bullets of the same shape will usualy have more mass without much more airflow resistance.
So they travel further with less bullet drop.

Obviously if it is so heavy it is significantly slower than a standard loading, then the initial velocity is a larger factor in that particular loading than the weight of the projectile.

There is a curve created by the pressure limitations of a loading. You will find the best projectile for a given range in that curve. Heavier than a certain point will drop more, and lighter past a specific point will drop more, at a given range, for the same shape and diameter projectile.
 
I'm certainly no physicist, but my attempt at an answer.

First, maybe it's helpful to exaggerate the air resistance to illustrate the point.

1. Suppose the air resistance is so great that it instantly overcomes the horizontal velocity of the bullet and decelerates it to 0 fps. The bullet would drop straight down to the ground.

2. Now suppose the wind is so great that firing a bullet at it is like throwing a nerf football at a tornado. The bullet exits the gun but is instantaneously decelerated and, in fact, blown back at the shooter and dropped to the ground someplace behind him.

In either case, how FAST the bullet dropped was not a function of its mass. Air resistance in the vertical direction was also negligible. Consequently, both bullets dropped in the same time (i.e., they were airborne for the same amount of time). However, how far the bullet traveled in the horizontal direction (i.e., whether the bullet stayed in one place and dropped straight down or whether it actually fell to the ground someplace behind the shooter) was a function of the air resistance.

Overcoming air resistance is defined by the ballistic coefficient (BC) of a bullet.

If you assume the following:

* BC is proportional to the ratio of the mass of a projectile to its shape; and

* Higher BC means less deceleration of a projectile and lower BC means more deceleration;

then given two bullets with the same size, same shape, same muzzle velocity, but different mass, the heavier bullet will have a higher BC and will lose less energy over a given distance than a lighter bullet. This means it should (i) travel farther overall, (ii) have a shorter time of flight to XXX yards, and (iii) hit harder at XXX yards. However, it should be airborne for the same amount of time as a lighter bullet.

Of course, I'm sure somebody out there actually knows a whole lot more about this than me. For example, I think bullets start to nose down at some point in their trajectory and drag can actually contribute to bullet lift. But that's above my pay grade.
 
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Gravity is a constant, both bullets drop at the same rate regardless of size shape or mass. Drop a BB and a bwoling ball from the same height and both hit the ground at the same time.
 
In a vacuum, certainly.

On planet Earth where air-resistance actually exists - different story.
 
Drop a BB and a bwoling ball from the same height and both hit the ground at the same time.
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Only for a little while.

If you dropped them both from an aircraft at several thousand feet it would be a different story.

The BB especialy if lead would actualy be denser and might actualy have a higher terminal velocity than the less dense bowling bowl, and as a result hit first, though I would have to double check that with the stats of the ball. Normaly the much larger sphere would have the advantage, but the bowling ball is made from much less dense material.

The bowling ball would of course have more energy when it hit because it is significantly heavier.


Now if both were made of of the same material, lead to keep it simple, the larger sphere would have a much higher terminal velocity, and the lead size bowling bowl would still be gaining significant increases in speed long after the lead BB approached its terminal velocity.


So they would not hit at the same speed. The lead bowling ball size sphere would hit far sooner while the slow BB was still falling, its air resistance reducing its increases of speed from the gravitational pull long before.
The difference would be greater the further up they were dropped from.

This does not really relate to the OP's question though from a bullet fired at traditional angles, merely to your comment.
 
Consider that we have two shooters shooting identical firearms with different weight bullets of identical shape. The lighter bullet is moving at 1150fps and the heavier bullet is moving at 750 fps.

Both shooters shoulder their weapons at the exact same height, firing across an absolutely flat surface. The lighter bullet hits the ground at exactly the same time as the heavier bullet. The lighter bullet is further from it's point of origin than the heavier.

The factors that are identical to both bullets are height of origin, or distance to fall to earth, shape of bullet, caliber, air resistance, and gravity, or acceleration towards the earth's core.

The different factors would be weight of bullet and velocity.

Depending on the accuracy of your measuring device the heavier bullet might strike the ground infinitesimally sooner than the lighter, because the heavier bullet's own gravity would have a stronger attractive force on the earth than the lighter bullet, but the difference would not be worth mentioning. No practical human measuring device could spot the difference.

Now get ye to a range!
 
The downward areodynamics of a bullet will affect how quickly it drops.

However, I don't see there being hardly any difference, especially when comparing two bullets of the same caliber, the heavier one just being longer. You have basically the same surface area due to weight looking at the bottom, and it isn' like the cone of air that forms around a spizter type bullet (which gave it such a nice range boost over older flat nose bullet types) you aren't going to have much of a difference at all in downward air resistance, so no difference per second of flight.

however, per unit of distance, because the lighter bullet is faster the time it takes to get from 0 to 100 yards is less, so less drop time
 
The factors that are identical to both bullets are height of origin, or distance to fall to earth, shape of bullet, caliber, air resistance, and gravity, or acceleration towards the earth's core.
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Actualy air resistance is proportional to speed, and increases dramaticly the faster the bullet is moving. So the forces working to slow it down are stronger.

Both would hit the ground at the same time, as you said, and the faster one should be further.

You started with too extreme of a spread in velocity though, because to overcome that dramatic difference with an unknown weight (that might not be proportionaly different because you never gave it) a very long distance would have to be traveled before you would see a difference between different weight projectiles. Perhaps a distance greater than the distance they will travel at a 90 degree angle, that all depends on what the range of the cartridge is.

As I said there is pressure limitation that create a curve that you must know to demonstrate it.
A faster bullet travels farther, and hence has less bullet drop over distance. However it is the median speed you must factor in, not the muzzle velocity.

Over distance a heavier projectile of the same shape will have lost much less of its total velocity. So over a long enough distance the heavier projectile will actualy have less drop because it has a higher ballistic coeffecient, and hence loses less velocity, traveling further before impacting the ground. Essentialy meaning the heavier initialy slower round can actualy have a higher median speed over the distance of travel.
You need to start with less difference in speed though to realize it at practical distances. 1150fps vs 750fps is too great at realistic ranges at ground level, especialy at pistol ranges (which I assume you are comparing at those velocities).

At most pistol ranges the faster lighter round will usualy have less drop.
At long rifle ranges the heavier rounds with a slightly lower initial velocity operating at the same pressures will actualy have less drop than a light projectile going faster because the median speed of the heavier projectile can actualy be higher over its traveled distance because it bleeds velocity slower.

That is why there is a perfect bullet weight for a specific range at normal operating pressures (if accuracy was the only concern, obviously heavier rounds also penetrate better and retain energy better over distance, yet faster ones have higher initial energy figures operating at the same pressures.)
 
Zoogster, but those aerodynamic forces act in specific directions, yes, the faster, the more resistance, but BOTH bullets are starting with ZERO vertical velocity, their foward resistance is insignificant in relation to vertical drop.
 
WOW what a turnout.....I worded the original post poorly so there has been some confusion as to what I am talking about, Let me try and clarify:

When I asked "Which will drop faster" I was referring to which one drops fast with respect to time, not distance. Since bullet drop is commonly referred to in shooting to be a function of distance I should have been more clear in my original post. The equations I derived were all functions of time not distance.



I thought Newton settled this particular debate centuries ago.

Everything falls at the same rate for a given weight.

Pound of feathers, a pound of lead... both hit the ground at the same time.
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In a vacuum everything drops at the same rate regardless of size and shape because there is not wind resistance. However through air, the time it takes to reach the ground IS dependent on both the shape of the object as well as the weight. A good example: take a sheet of paper, see how long it takes to hit the ground, then ball it up and try again. The ball hits faster because its shape has less air resistance.


At any point in TIME any two bullets will have dropped the EXACT same distance (vertical displacement) regardless of their weight, size, or muzzle velocities.
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Incorrect a heavier bullet will have dropped farther than a lighter bullet at a given time IF THEY ARE BOTH THE SAME SHAPE AND SIZE.

Long ago Galileo proved that objects of different weights drop at the same speed.
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ONLY IN A VACUUM, through air both size and weight matter…don’t believe me, if size , shape and weight don’t matter and everything falls at the same speed, then how do parachutes work?....answer, air resistance. This opposing force is very small and in many cases (such as objects falling short distances) the difference is so small that it can not be observed by the naked eye, most of the work done with deriving air resistance came from the late 19th century, the main reason being that they did not have means that were accurate enough to determine this difference during earlier times ( ie Galileo’s time)

I think if more people would apply practical ballistics and experience instead of trying to dazzle us with their prowess in "college level physics and calculus" theory, their proficiency at the range and in the field would possibly improve.
No one has addressed the hypothetical transition through transonic that may occur with one bullet weight and not the other, at least not at the same time. That may have an effect on the mathmatical outcome. We live in the real world where air resistance is different at subsonic compared to supersonic.
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1st, I am not trying to dazzle anyone just clear up the misconcetption people have that bullets drop at the same rate reguardless of weight, that is only true if you neglect air resistance, 2nd look up some of my range reports, my performance at the range is quite good (when Im having a good day :D 3rd, there is no vertical transition through sonic speeds, a bullet is being fired supersonically horizontally not vertically.

The first fatal flaw i see with your work is the incorrect assumption that "air resistance" is BV where B is a constant based solely on shape and air density. What you are describing is "drag coefficient"
Instead of drag coefficient, you need to use "ballistic coefficient"
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Actually b in this equation is neither the drag coefficient nor the ballistic coefficient, it is a function of air properties as well as the shape of the object. If you try to use either the ballistic coefficient or the drag coefficient you will see that the units do not add up, your force equation will have units of velocity in it. b is expressed with the units N-sec/m (for metric) both the Drag coefficient and ballistic coefficient are unitless numbers.

Wait a second. Isn't the "air resistance" that would effect the speed with which the bullet drops the vertical air resistance?
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Yes, that is the air resistance that is used in the original post, vertical air resistance, not horizontal


Everything that is usually taught in basic physics class is done ignoring air resistance. The reason: most kids taking physics haven't had differential equations or calculus yet!

Anyone who still disagrees with me that air resistance has an impact on the time it takes an object to reach the ground should try looking up "Free fall with Air resistance" I am sure that there are books out there that have the same equations I came up with. ( I know there is at least one, because way back when this was a test problem in my differential equations class ;))

Now I will restate the conditions for this statement to be true which will hopefully clear up any confusion that I created from my wording:

"Heavier bullets drop faster with respect to time than lighter bullets if both bullets are of the same shape and size"
 
Uh-oh. Line item quotes always spell the end of any meaning thread content.

I'm in awe this discussion has gone on this long, given the basic laws of gravity and all (that we learned in like 1st grade or something).


-T.
 
Of course in the real world, bullets are different shapes and sizes so they all "fall" at different rates, vertical air resistance is so small that it is "washed out" by the fact that bullets travel at different speeds, so perceived bullet drop on paper comes from the fact that one bullet just "got there faster" so it didn't have as much time to fall. (which was covered by many previous posts)

Thanks to all that took an interest in these posts! :)

The main purpose of starting this thread was to inform people that because of air resistance all objects to not fall at the same rate. This misconception has come from forgetting the fine print in those basic physics problems that say "neglecting air resistance if two objects....."
 
Going to go ahead and agree with Garandowner on this one. There is definitely some interesting ideas on physics in here, that is for sure.
The main purpose of starting this thread was to inform people that because of air resistance all objects to not fall at the same rate. This misconception has come from forgetting the fine print in those basic physics problems that say "neglecting air resistance if two objects....."
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Ding ding ding! We have a winner!!!
 
Hey,
Once you guys added fluid dynamics (AIR) all bets are off, as it's too complex to predict; hence, all the counter examples. :uhoh:
Best,
Rob
 
not really Rob, because the vertical air resistance starts off at ZERO since the bullets start with no drop. and since we are talking about shooting at an elevation of an entire 5 feet, it means that their vertical velocity when they hit the ground will be so slow, that air resistance vetically can still be counted as Zero.
 
It's all been said but the short version is...

Two rounds fired from different guns, example: one a 220 swift and the other a .45 LC. Both with identical trajectory, fired over a flat surface and fired at the exact same time, will hit the ground at the same time.

The primary difference will be the .45 will hit the ground about a 100 yards away and the 220 will hit the ground several hundred yards out, but that is due to the velocity of the round and not gravity which acts equally on all objects.
 
Two rounds fired from different guns, example: one a 220 swift and the other a .45 LC. Both with identical trajectory, fired over a flat surface and fired at the exact same time, will hit the ground at the same time.
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As long as both bullets leave the barrel traveling perfectly parallel to the ground. If there is any upward component of the velocity vector, then that will cause a longer flight time (up to several seconds).
 
Now, which weighs more? A pound of lead, a pound of copper, a pound of depleted uranium, or a pound of tungsten?
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In a vacuum, or in an atmosphere? :)

(Considering that the U.S. pound is officially a unit of mass, not weight.)
 
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