Where can i get the machine that measures joules?

Jermaine · Where can i get the machine that measures joules?

or energy of the shot

wabbiter

any gun shop will sell a CHRONOGRAPH... its up to you how much you want to pay as there are several different types....mack

fish

i believe theres a mathematical formula that uses the velocity x the weight of the projectile to come up with the joules of energy.

wabbiter

check this out .http://www.unitconversion.org/energy/joules-to-foot-pounds-conversion....mack

JoergS

Actually, you can use a laptop with an audio microphone to measure the time difference between the shot and the hit. This will give you the speed of the bullet. Meters per second is the value you need to find out.

Next, you weigh the bullet. Kilogramms is what you need.

Then, you use this formula:

0,5*Weight*Speed*Speed

So if you use a 10 Gramm bullet that flies at 60 Meters per second, you get

0,5*0,001kg * 60m/s * 60 m/s = 18 Joules

Jörg

Adam

If you want the answer in foot pounds instead of joules use this:

0.5 x mass x speed x speed then divide the result by 32.17 (acceleration due to gravity in feet per second)

Mass needs to be measured in pounds (Imperial lBs there are 7000 grains or 16oz in a pound). Speed needs to be measured in feet per second.

So a half ounce ball moving at 200fps = 0.03125lBs x 40,000 fps/s = 625 foot poundals, divide by 32.17 to get 19.42 foot pounds.

If you already know the energy in joules you can simply divide by 1.35 to get foot pounds - e.g. 18 joules = 13.3lbft

Nice idea about the laptop - to be really accurate place the laptop or the microphone halfway between the shooting position and the target to eliminate the speed of sound from the equation. The speed of sound in air is around 1125fps so when we're talking about speeds of over 200fps for the projectile you can be as much as a fifth out in your calculations unless you eliminate the distance the sound has to travel.

Cheers,