Calculate rifle free recoil energy from bullet weight, optional powder charge, muzzle velocity, and gun weight in foot-pounds or joules.

Rifle Recoil Calculator

Enter the following values to calculate Free Recoil Energy







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Rifle Recoil Formula

The following formula is used to estimate a rifle’s free recoil energy (a common approximation that includes bullet momentum and an estimated powder-gas contribution):

RE = ((BW * MV + 4700 * PW)^2) / (2 * GW * g * 7000^2)

Variables:

  • RE is the free recoil energy (foot-pounds)
  • BW is the bullet weight (grains)
  • PW is the powder charge weight (grains)
  • MV is the muzzle velocity (feet per second)
  • GW is the gun weight (pounds)
  • g is the acceleration due to gravity (32.174 feet per second squared)
  • 4700 is an approximate powder-gas velocity in feet per second (a commonly used rule-of-thumb value for rifles)

To calculate free recoil energy, first convert BW and PW from grains to pounds by dividing by 7000. Then compute the ejecta term (Wb × MV + Wp × 4700), square it, and divide by (2 × GW × g). (If PW is unknown, you can set it to 0 to get a bullet-only recoil-energy estimate.)

What is Rifle Recoil?

Rifle recoil, or “kick,” is the backward momentum experienced by a shooter when a rifle is fired. It is a result of the conservation of momentum where the forward momentum of the bullet and gases is matched by an equal and opposite momentum of the rifle. Recoil energy is an important consideration for shooters as it can affect the accuracy of follow-up shots and the shooter’s comfort.

How to Calculate Rifle Recoil?

The following steps outline how to calculate the Rifle Recoil Energy.

  1. First, determine the bullet weight (BW) in grains.
  2. Next, determine the powder charge weight (PW) in grains (if unknown, use 0 for a bullet-only estimate).
  3. Next, determine the muzzle velocity (MV) in feet per second.
  4. Next, determine the gun weight (GW) in pounds.
  5. Next, gather the formula from above = RE = ((BW * MV + 4700 * PW)^2) / (2 * GW * g * 7000^2).
  6. Finally, calculate the Rifle Recoil Energy (RE) in foot-pounds.
  7. After inserting the variables and calculating the result, check your answer with the calculator above.

Example Problem:

Use the following variables as an example problem to test your knowledge.

Bullet Weight (BW) = 150 grains

Powder Weight (PW) = 50 grains

Muzzle Velocity (MV) = 2800 feet per second

Gun Weight (GW) = 7 pounds