Calculate the free recoil energy and velocity of a firearm based on load data.
Last updated: March 2026 | By ForgeCalc Engineering
Free recoil energy is a mathematical representation of the kinetic energy of a firearm as it moves backward when fired. It is a direct application of the conservation of momentum: for every action (the bullet and gases moving forward), there is an equal and opposite reaction (the gun moving backward).
While "felt recoil" is subjective and depends on stock design and recoil pads, free recoil energy is an objective measurement that allows for the comparison of different calibers and loads.
Recoil energy is inversely proportional to the weight of the firearm. Doubling the weight of the gun will cut the recoil energy in half.
The gases produced by the burning powder also have mass and are ejected at very high velocities, contributing significantly to the total momentum.
Most shooters find recoil energy under 15 ft-lbs to be comfortable. Above 20 ft-lbs is considered 'stout', and over 40 ft-lbs is generally considered heavy.
Indirectly. A longer barrel usually increases muzzle velocity (increasing recoil) but also adds weight to the firearm (decreasing recoil).
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