How to Calculate Shotgun Recoil

Shotgun recoil is dependent on the type of shotgun and type of ammunition.

A shotgun is a firearm which uses a round cylindrical cartridge to fire various types of bullets including groups of pellets, solid bullets and crowd-control weighted bags. Shotguns are long two-handed firearms and can have different barrel lengths and widths depending on type and model. Shotguns, like most firearms, produce recoil when fired. Recoil is a physical force which pushes back on the gun and user as the bullet is fired. The recoil force can be broken into recoil impulse, recoil velocity and recoil energy.

Instructions

1. Find the muzzle velocity, measured in feet per second and gun mass in pounds, of the gun. This information may be located online, in the gun manual or from the manufacturer.

2. Find the shot mass (grains), wad mass (grains) and charge mass (grains) of the ammunition. This information is commonly listed on the ammunition box or is available from the manufacturer.

3. Multiply the charge mass by 1.5 and add it to the shot mass and wad mass.

4. Multiply this value by the muzzle velocity. Divide by 32.17 to account for gravity and multiply by 7,000 to convert grains to pounds. This value is the recoil impulse and is measured in milliseconds.

5. Multiply the recoil impulse by 32.17 and divide by the gun mass. This value is the recoil velocity feet per second.

6. Square the recoil velocity and multiply by the gun mass. Divide by 64.34 which is double the gravitational constant. This value is the recoil energy and is measured in foot-pounds. 

References

• Ballistic Formulas: Shotgun Recoil Energy, Impulse & Velocity Calculator