Bullet Energy Calculator

[Col Defender]

I used to have a simple to use bullet energy calculator on my computer. All I had to do was enter the bullet weight and the muzzle velocity and it instantly gave me the energy of the bullet at the muzzle in fps. I lost it!

Does anyone have a link?

I think it was called something like a :Bullet Energy Comparator -

Thanks

Steve

 

[Col Defender]

Woops energy should be in ft/lbs not fps!

 

[Damn Yankee]

Mash Here

http://www.lasc.us/ConversionTables.htm

http://www.firearmexpertwitness.com/customguns/calcnrg.html

Google is your friend.

 

[cp1969]

It's not a complicated calculation:

Kinetic energy = ½*M*V²

V = velocity, in feet per second
M = bullet mass, in slugs

To convert bullet weight to slugs, divide the bullet's weight in grains by 7000 (the number of grains in a pound) to get the bullet's weight in pounds, then divide that result by 32.2 to convert it to a unit of mass.

So if you're in a position where you need to calculate energy, you can do it with the calculator on your phone, or an old-fangled pencil if need be:

Multiply the velocity by itself. Multiply that by bullet weight. Divide by 7000. Divide by 32.2. Multiply by 1/2. That's it. If you want to do it over and over, combine all the numbers in the denominator into a single constant (2*32.2*7000 = 450,800), then all you have to do is square the velocity, multiply by bullet weight in grains and divide by 450800.

 

[nicky4968]

On your slide rule, square the velocity. Multiply that times the bullet weight. Divide by 448.
(A 158 grain bullet at 900 fps and a 200 grain bullet at 800 fps seem to come out the same.)

 

[505Gibbs]

On your slide rule, square the velocity. Multiply that times the bullet weight. Divide by 448.
(A 158 grain bullet at 900 fps and a 200 grain bullet at 800 fps seem to come out the same.)

Now here is a statement of age - a slide rule!!
I only have two so I guess I'm that old as well.
Nice to see somerthing besides the word - calculator.
If you have Excel - you could use that as a program.

 

[Rule3]

Here is one with a KO factor.

Energy Calculator

 

[cp1969]

On your slide rule, square the velocity. Multiply that times the bullet weight. Divide by 448.
(A 158 grain bullet at 900 fps and a 200 grain bullet at 800 fps seem to come out the same.)

I don't have a slide rule to try that on, but if I do the same thing on a calculator, a 255 gr., 1000 fps load has over 569,000 foot-lb of energy.

That seems high.

 

[OKFC05]

I don't have a slide rule to try that on, but if I do the same thing on a calculator, a 255 gr., 1000 fps load has over 569,000 foot-lb of energy.

That seems high.

It is.
Just use the claculator posted above that takes care of the units conversion.
Energy Calculator

 

[USAF385]

Here's what I do:

Grain x velocity squared / 450436

I got 450436 by multiplying two times the acceleration of gravity (I used 32.174 fps) by 7,000 which is how many grains are in a pound.

Example: 255 grain at 1000 fps

255 x 1000 x 1000 / 450436 = 566 ft-lbs


Another example: 158 grain at 1450 fps

158 x 1450 x 1450 / 450436 = 737.5 ft-lbs

 

[JD 500]

hornady has one here : Ballistics Calculator - Hornady Manufacturing, Inc