It’s been a while since I did some math. For those of you that don’t remember, don’t care or are not interested, that is fine. These are real experiments and real life applications of physics and mathematics. Guess what, they are pretty simple as things go too.

I picked up a chronograph this week. This is a tool that measures how fast a projectile is travelling. From that, I will be able to calculate energy and measure the consistency of my reloads. I think that I am going to get some interesting data from this. Energy is the real life equalizer when comparing different calibers like fast and light versus slow and heavy or bullet to bullet size.

Sir Isaac Newton figured it out a long time ago. The formula for kinetic energy is 1/2 mass * velocity * velocity. At the risk of being boring, mass and weight are not the same thing. Mass is really how much space something takes. Weight is mass plus gravity (really mass times gravity). So, when we measure something in pounds or grains, we need to divide by a constant of earth’s gravitational pull as well. If we were to use the metric system, we wouldn’t have to do this extra conversion.

This describes the energy calculation above.

Essentially, all I have to do is know my bullet weight in grains and measure my velocities and plug it into the formula above to calculate energy. I am going to demonstrate some more math later when I get more data but I will talk about it when I get there. I don’t want to get too heavy too quickly.

You don’t have to understand my math to use it, just plug in values into the formula and calculate. My math was proving that the formula for kinetic energy was applicable to my situation. The actual scientific unit for energy is a Joule. You will have to convert all those units to metric to look at it in that unit. That is a whole different post, but it can be done.

Here are some quick examples for perspective

  • 22LR – 130 ft lb
  • 9mm- 355 ft lb
  • 357 magnum – 583 ft lb
  • 30-06 – 2913 ft lb

The above are just examples with nominal weight bullets and velocities. Energy can change with different weight bullets and particularly more velocity (because it is a squared value). This mean shooting a 22lr from a handgun and a rifle are going to have dramatically different energy values because in theory, you are going to get a more efficient powder burn from a rifle and have significantly more velocity.

I do have some planned experiments in mind first. I want to measure velocities of my pellet rifle. The first thing I am interested in is how consistent are the velocities shot to shot. The second thing I am interested in are how much the velocities change with different pellets both weight and design. I am also interested in velocities at the muzzle vs the target or how much loss there is over distance.

I have some other experiments planned for my BB/Pellet rifle. It takes 10 pumps to get to full power. I want to see the velocity difference in each pump and the consistency of that particular rifle. Or said another way 1 pump = x fps, 2 pumps = y fps, 3 pumps = z fps. I plan to use that data to tell me how much difference there is (or isn’t) for follow-up shots and accuracy.

Finally, I want to do some checking of my reloads. I want to know how consistently I am making ammunition. I would be interested in checking factory loads and comparing my work to the published data. There is a ton on science and information that can be gained from this tool.

I definitely don’t see myself using this each time I go to the range. However, I do see myself using it until I get a comfort level of consistency. Once I establish a baseline that seems to be predictable, I will be an informed shooter with data rather than what I think I know.

End Your Programming Routine: It has been a long time since I tried to type math equations into a word processing program. I had to do it routinely in college, but I really haven’t had much use since then. Word has improved quite a bit in twenty-five years. I know, it is kind of hard to get excited about reading someone else doing math, but for me it is like reviving old brain cells. I wont have a data set this week, but soon.