Velocity Loss

[Zonie]

Every so often, someone says something like "Those big balls loose their velocity faster than little balls because they are poking a bigger hole thru the air.", or something like that.

Having a ballistics program which was designed for round balls, I got to thinking, "What really happens to a balls velocity at 100 yards if the muzzle velocity was a constant 1500 feet per second? How much velocity will different size balls loose?"

With this in mind, I set the program for a muzzle velocity of 1500 FPS and inserted different common ball sizes and then recorded the 100 yard velocitys.
The following lists the ball size, the velocity lost and that losses percentage of the initial 1500 FPS.

cal, velocity loss, percentage lost

.310, 714, 47.6%
.350, 674, 44.9%
.440, 605, 40.3%
.490, 574, 38.3%
.530, 553, 36.9%
.570, 533, 35.3%
.610, 516, 34.4%
.780, 457, 30.5%

From this, it is apparent that the larger the ball is, the less velocity it looses given a fixed muzzle velocity.

Because all calibers don't shoot at the same velocity, I'll see what percentage of loss is present for some more practical muzzle velocities based on caliber later.

zonie

 

[KW]

That's pretty cool!!!!! Is that program available for anyone?

 

[bwhoffman]

I would'nt mind playing with it as well!

 

[Wes/Tex]

That list pretty well confirms the resluts I've found over the years. I always put it down to mass-over-velocity...balls for a musket always got down range with a lot more OOMPH than smaller bored guns! Thansk for the chart. Wes

 

[Zonie]

This is the link to the program.
It is FREE and it was created by one of our members. It will run on windows 98 and XP depending on the version you click on so read the material.
I don't know if it will run on the new PCs but you can try it.

I am not aware of any strings attached to the download or the use of this program but it is designed for roundballs.

If you enter the balls diameter, it automatically calculates the balls weight for you.

FREE BALLISTICS PROGRAM

You will notice that you can enter the cross-wind velocity by typing X3 (for a 3 mile/hour wind). Actually you can enter any velocity of cross wind you want by changing the number.
You will be amazed at the effects.

zonie

 

[Zonie]

OK. For some more practical velocities I looked up some fairly hot loads in the BLACK POWDER HANDBOOK & LOADING MANUAL by Lyman.

The first value is the caliber followed by the muzzle velocity followed by the velocity loss at 100 yards followed by the percentage of velocity lost. (Plain as mud, I know).

cal, MV, loss, percentage

.310, 2100 fps, 1207 fps, 57.5%
.440, 1900 fps, 922 fps, 48.5%
.490, 1650 fps, 687 fps, 41.6%
.535, 1550 fps, 587 fps, 37.9%
.570, 1400 fps, 461 fps, 32.9%
.690, 960 fps, 177 fps, 18.4% (ball in 12 guage)

This would appear to say that the larger calibers maintain substantially more of their initial velocity than the smaller bored guns.

zonie

 

[BrownBear]

Sure makes a feller feel smart when he see some science that agrees with his opinion.

Thanks zonie!

 

[Dave Rosenthal]

The biggest BP rifles I know are located on WW2 Iowa Class Battleships. They a 50 caliber 16" rifles that can launch a 2800 pound AP projectile for approx 30 MILES, and at 25 miles do quite accurate work! The computations needed to get a salvo on target required that the firing control guys take into concern the rotation of the Earth underneath the salvo as it was traveling those 25+ miles!

Your theory about loss of velocity with those little lead balls is quite correct, otherwise the Battleship's salvo would fall into the ocean long before it could reach a target on land. Each round weighed 19,600,000 grains (7,000 x 2800).

So Mr. Zonie, you're right! Bigger is better! Now I wonder if anyone built a chrono big enough to fire a 16" round through?? :rotf:

You and all have a fine day!

Dave

 

[roundball]

From this, it is apparent that the larger the ball is, the less velocity it looses given a fixed muzzle velocity.

A pretty good analogy about that very thing is to remember a ping pong ball & a golf ball...same size, far different weights...throw each one as hard as you can (same "muzzle" velocity)...no question about the outcome.

 

[rabbit03]

Thanks Zonie, you may just have given the scientific answer to the WHOMPABILITY factor we were talking about!

:thumbsup:

rabbit03

 

Yes sir, I would bet on the golf ball. I think I will keep shooting my .58 with the 90-120 gr loads. Unless of course, I want to really drive that big ball through a bunch of stakes. Then I'll drop the powder charge down to, say, 50 grains for the maximum penetration. :haha:

 

[bob1961]

This is the link to the program.
It is FREE
FREE BALLISTICS PROGRAM

keep getting page cannot be displayed :v ..............bob

 

[Zonie]

Bob: You might try going to the free program using the post in this link
Old Zonie Link to FREE BALLISTICS

It has an older link to the site which jumped to the newer link I posted above.

When I selected the link in your post, it zapped me to the right place so your problem may be related to your computer. Maybe your cookies have flour beetles in them or something??

zonie

 

[bpesteve]

Thanks Zonie! The "Static electricity -vs- Black Powder" experiment page there is another classic.

:hatsoff:

 

[bob1961]

thx zonie the link in the old post worked :hatsoff: :v ..............bob

 

[Zonie]

When you guys get the program working, put in a X10 (enter) and notice how much drift the ball will have at 100 yards. The basic .45 at 1800 ft/sec MV is blown off course by over 13 inches on my printout.

Oh, speaking of printout, one method I've used is to enlarge the window to the max and then poke my "Prt Scrn" button. That copies the screen image into the "copy" memory.
Then, select the "Start" button, then "Programs", then "Accessories", then "Paint".

When the Paint screen opens, go up to the "EDIT" button and poke it. Select the "PASTE" button and the computer screen image will suddenly appear.
You are looking at a picture of your computer screen so don't try to operate anything on the picture. It won't work. The real screen peeking out around the edges of the picture is still your active screen.

If the data image is black with white lettering, go up to the top and select "IMAGE", then select "Invert Colors". Suddenly, you have white with black letters (and a weird looking remaining computer screen).

You can save and print the results, but you will waste ink printing the extra picture so, file your picture somewhere.
At this stage, I open one of my Photo editors and then open the saved picture. I then crop the picture to remove the extra stuff leaving only the data, save it and then print it.

There may be better ways to do this but I don't know what they are.

Have fun.
zonie

 

[Slamfire]

One problem is that wind hardly ever blows at 90 degrees to the line of fire. That means there is a component pushing the projectile sideways and another component either pushing the projectile or opposing it. Simple ballistics programs are unable to take these wind components into account.

 

[Zonie]

Picky picky picky.
It's simple. If the wind is blowing at an angle towards you or away from you, you merely determine the angle relative to the shot. Lets say it is blowing towards your face more than from the side and it is coming from 10 o'clock. 10 o'clock is about a 60 degree angle. (each "o'clock" is 30 degrees"

Measure the velocity of the wind. Let's say it is 8 MPH.

Now, multiply the velocity times the sine of the angle, in this case, 60 degrees, so we have sin60 degrees X 8 = .866 X 8 = 6.9 MPH.

If the wind was coming from 7 o'clock the angle would be 30 degrees so the right/left speed would be 8 MPH X sin 30 degrees = 8 X .500 = 4 MPH. :grin:

Yah, I know. Nobody likes a smart ass. :rotf:

Of course, in the real world, a person isn't going to be lugging their computer around out there in the boons, so, I guess we will just have to do it the old fashioned way. By Guess and By Golly.
zonie

 

[Slamfire]

I don't carry a table of sines, cosines, tangents and cotangent in my possibles bag, but I can tote some graph paper and a pencil. :shake: :blah:

 

[Wes/Tex]

I don't carry a table of sines, cosines, tangents and cotangent in my possibles bag, but I can tote some graph paper and a pencil. :shake: :blah:

Not a problem! Just remember that you divide the width by the square root of 16 leap-year tangents...no, that's how you figure how far your thumb goes down the front hole! :rotf: