Free Recoil Energy - SAAMI
Free Recoil Energy is really kinetic energy and so can be expressed mathematically as:
F.R.E. = 1/2MV^2
Where:
M = is the mass (or the weight of the firearm divided by 32.17) and
V = is the velocity of the recoiling firearm,
To determine the velocity of the recoiling firearm we can use the formula:
V =
Where:
We = Weight (in grains) of the ejecta (bullet or shot and wad column)
Ve = Velocity of ejecta in feet per second
Wpg = Weight of propellant gases
Vpg = Velocity (fps) of propellant gases
7000 = Conversion factor for grains to pounds
Wf = Weight of firearm in pounds