Optimal Bullet Velocity Formula (OGW Reversed)

On this page, you will find a basic calculator designed to run the Optimal Bullet Velocity Formula (OBV) which is basically Matunas Optimal Game Weight Formula but reversed.

This is how I prefer to run the formula and I’ll explain why later.

Below the calculator are the instructions on how to use it, a video on the OGW formula and an article about OGW.



Optimal Bullet Velocity Calculator Instructions:

Simply, enter the weight of your target animal, the bullet weight in grains, and the OBV row will self populate and give you an Optimal Bullet Velocity.

Now you simply cross-reference your OBV with your ballistic data to ascertain your maximum effective range.

By the way…if you work in kgs instead of lbs, I’ve got you covered with a weight converter as well. Simply do your kg to lbs conversion first, then crack on with the OBV Calculator.

When hunting at longer distances, it is extremely important that you are aware of the limitations of your rifle/cartridge combination and of course yourself.

This will help to avoid unnecessary situations where an animal is injured, causing it to suffer.

Traditionally, many hunters used the Optimal Game Weight Formula developed by Edward A Matunas comes in.

You can find out more about the Matunas Optimal Game Weight Formula by clicking here.

Now…as good as the OGW formula is, it does have its limitations (as do all other hunting formulas).

Essentially, no formula can account for bullet design/construction or shot placement.

However, the original OGW formula is a great “indicator” as to the suitability of a given cartridge for various sized game, which is why it has been adopted by so many hunters.

Matunas even developed a varmint version of the OGW formula

Calculate your Optimal Bullet Velocity (OBV) so you can work out your maximum range for game like Red Deer. (Credit Mehmet Karatay).

BUT personally, I find the original OGW formula a little cumbersome.

I don’t like “tweaking” the velocity data until I reach the weight of the game I intend to hunt.

So…I “reversed” the formula.

This allows you to simply enter the weight of the animal you intend to hunt (because most hunters will know the likely weight of their intended target), and then the bullet weight in grains.

This will give you an Optimal Bullet Velocity (OBV) at which you can shoot that sized animal, and you simply cross-reference that OBV to your ballistic data.

So…lets look at the formulas…

Optimal Bullet Velocity Formula:

(Game Weight ÷ 1.5×1012 ÷ Projectile Weight2)3

Optimal Bullet Velocity Formula for Varmints:

(Game Weight ÷ 5×1013 ÷ Projectile Weight2)3

Now…as you can see, this is some pretty involved math!

I don’t know about you but math isn’t really my thing. I’d much rather be shooting than running calculations or formulas.

This is why I prefer to use the Optimal Bullet Velocity Formula (OBV) calculator instead.

Now, as with all of the converters and calculators provided on the Skill At Arms website, these calculators aren’t the best-looking things in the world, but they WORK! ; )

I’m not a web developer so until such time as I can afford to hire a web developer to “pretty” these calculators up, you’ll have to make do.

If you prefer to work in m/s instead of fps OR kgs instead of lbs, no drama…I’ve got you covered with converters for those units also.



Take care…


P.S. I hope you found the Optimal Bullet Velocity Calculators useful. If you did, I would appreciate it if you would SHARE this page with friends who may be interested.


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