Calculate damage values from bullet velocity and size

Question

I'm trying to make a top-down game using Javascript and Pixi which involves multiple different guns.

Instead of giving each gun an individual damage value, I wanted to calculate the damage by the bullet's dimensions and velocity as it leaves the gun (which is all available on Wikipedia).

However, I'm having issues where despite some damage values looking okay (e.g. UMP-45 has about 40, Mac-11 has about 22, TEC-9 has around 35 and Glock has about the same) some values are too high to offer a challenge to the player (AK-47 has 110, M4A1 has 220, Desert Eagle has 100+).

The current calculation I'm using is: \$ \frac{velocity \times bullet\ length}{1000} \times \frac{bullet\ radius}{2}\$
Or in pseudocode: (velocity*bulletLength/1000)*(bulletRadius/2)

Anyone have any ideas for tackling this issue, or is it best to just use straightforward values? The game would be a horde-like sandbox game, so the damage values can't be too low or it would be almost impossible.

Answer 1

AKs and M4s are very strong. If you've ever played with an FPS like COD, then you know that you can't really do anything useful against a person with a higher end weapon using a pistol.

To balance things you could make the ammo for bigger guns more costy

Answer 2

You could change your calculation to make it more fair. That is just trial and error until you are pleased.

What are the properties common to weapons you want to reduce? If you realize bullet size for example has too much impact, use sqrt(bulletradius) instead, change your values a little bit, see if it fits, then try again if not, until you finally get the formula you want.

Answer 3

http://www.shooterscalculator.com/bullet-kinetic-energy.php It's a bullet kinetic energy calculator.

But I suggest to put all results of calculation to game configs. It is more easy way to balance things. Not reason to re-calculate already calculated things.

Then use pre-defined shapes as multiplier. Let's say you have shape1 = 0.8 and shape2 = 1.4, and you have a flying bullet with kinetic energy = 10; then your damage = 10 * shape1 = 8; or same bullet with different shape will be 10 * shape2 = 14. Same value you can also use to calculate reducing speed of the bullet.

Answer 4

It might sound obvious, but as a game designer, you're in control of the game design.
For the sake of simplicity, games are not accurate representation of reality*.

You can change another stat of the ammo/weapon (cost, reload time, etc.) for balance, but you can also change stat of the ammo itself such as damage dealt, muzzle velocity, etc. to achieve balance within your game even if that contradicts real-life statistics.

In the end, don't forget that it's all up to you and to meat what goals you've set for your game: a more realistic game should obviously try to stick to real-life as possible, but there is a balance to find between realism and gameplay, because no matter how realistic you want your game to be, it won't be real-life.

(*) Keep in mind that althought games are inspired by reality, they do not mimic it 100%. IRL a bullet in your body might incapacitate you... But it might also just make you feel pain and 9 more extra bullet would be needed to stop you.
This would hold for different weapons: a 9mm Parabellum bullet might kill you while a 12.7mm bullet might only wound you.