To be able to work out how much energy/power your airgun is producing, you first need to know two things.....the pellet weight in grains, and the velocity (in feet per second ) that the pellet is exiting the muzzle of your airgun.

When you know those two figures, you can then use the following formula to arrive at how much power your airgun is giving with that particular pellet.

The formula is.....Velocity x Velocity x Pellet Weight divided by 450240

For example, let's say Your airgun is doing 614fps using a 14.3 grain pellet.

So 614 multiplied by 614 multiplied by 14.3 then divided by 450240 = 11.97

We have now worked out that a 14.3gn pellet travelling at 614fps gives 11.97ftlbs energy.

Lets try another example of a 15.9gn pellet at 575fps

575 x 575 x 15.9 divided by 450240 = 11.67ftlbs

Please be aware that using different pellets can effect the power output of your airgun........ the airgun may be legal with brand X, but may be over the limit if you switched to brand Z.

It is the users responsibility to ensure their airgun complies with the Law, which in the UK is 12ftlbs for rifles, and 6ftlbs for pistols.