Bullet Velocity Estimation Tool

To use this tool, enter a bullet weight and velocity for a known load. Then enter the bullet weight of the bullet whose velocity you want to estimate.

About the Velocity Estimation Calculator

How does it work?

This calculator is a simple estimator. It's based on the assumption that a rifle will impart the same amount of kinetic energy to both bullets.

The equation used is:

$$v_{new} = \sqrt{m_{known}v_{known}^2 \over m_{new}}$$

Where the variables are as follows:

\(v_{new}\) the new bullet's velocity (what we want to compute)
\(v_{known}\) the velocity of the known bullet - measure this with a chronograph
\(m_{new}\) the new bullet's weight
\(m_{known}\) the known bullet's weight

For example, if we know our 185 grain bullet shoots at 2,775 fps out of our rifle, and we'd like to estimate the velocity of a 200 grain bullet we'd like to try, \(v_{known}\) is 2,775, \(m_{known}\) is 185, and \(m_{new}\) is 200. The calculated \(v_{new}\) should turn out to be 2,669.

This seems pretty rough. Is it accurate?

No, not really. At best it should be considered a rule of thumb or an estimate. It's a quick and dirty sanity check if you're thinking about trying a new bullet and want to know about how much velocity you will gain or lose.

Are there better ways to estimate velocity?

Yes, but you're going to need to get your wallet out. QuickLOAD software is an internal ballistics package that will allow you to estimate muzzle velocity and a whole host of other things (like chamber pressure and barrel time) based on detailed inputs (powder, charge, case dimensions, bullet dimensions, etc.). We find it highly valuable and worth the price. It's not perfect but it will get you much better results than this simple calculator.

So I have a velocity estimate, now what?

Well, one thing you can do is use our bullet comparator tool to see what the differences in ballistic performance is likely to be if you switch bullets. It's a ballistics calculator that's been designed to make comparing two bullets easier.