Air shooters often require calculators. If the weight and flight speed of a projectile are known then it is possible to calculate the muzzle energy in foot / pounds (or Joules if you prefer metric). Users might wish to determine one value based on another - so for example figure out the highest grain weight of a projectile that can be used for a particular speed and muzzle energy. Other calculators allow you to determine (both ways) flight time and/or distance assuming you know the speed of of the projectile - which can be useful if you need to know the time it will take a projectile to cross a fixed gap.

The calculators default to employing imperial values (foot pounds, feet per second (f/s) or inches when it comes to fixed distances) but there is an option to switch to metric (joules, metres per second (m/s) and mm for fixed distances). It is worth highlighting that projectile weight is always measured in grains (so, use the grains/grams conversion if you only know the weight of your projectile in grams).

Different countries have different legal limits or restrictions on air guns - so make sure you find out what applies in your jurisdiction... wherever that may be.

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Imperial employs ft/lb for muzzle energy, feet per second (f/s) for speed and inches for fixed distance. If you switch to metric units, then use joules for muzzle energy, metres-per-second (m/s) for speed and mm for fixed distances.

Note that projectile weights are always expressed in Grains regardless of imperial or metric being selected.

Grains

Grams

(knowing weight and speed)

Weight (Grains)

Speed (f/s)

Result

(knowing weight and muzzle energy)

Weight (Grains)

ME (ft/lb)

Result

(knowing speed and muzzle energy)

Speed (f/s)

ME (ft/lb)

Result

(knowing Speed and Distance)

Speed (f/s)

Distance (inch)

Result

(knowing Speed and time using the units below)

Speed (f/s)

Time (S)

Result

UK 12 ft/lb
UK 6 ft/lb
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