I put together formulas in Excel to do this but they don't seem to work out 100%.

Anyone know of any that are posted so I can compare notes???

  answer1 = (velocity * (bulletweight + 1.75 * powderweight)) ^ 2
  answer2 = 64.348 * weaponweight
  recoil energy in ft.lbs = answer1 / answer2

This one works for most rifle velocities.
   

Basic physics.  Newton's First Law.  Only the velocity of the powder mass depends on pressure at the muzzle, anywhere from 5500 ft/sec for a high powered rifle to 3000 ft/sec for a pistol.

Note, the product of the mass and velocity of the powder and bullet must equal the product of the mass of the firearm and its free recoil velocity.  Knowing this free recoil velocity, one can determine free recoil energy.

AeroE: Thank you for providing the links. My numbers do match when I plug them into the links.

I was using some data to cross check my formulas out of Hatcher's Notebook and the numbers do not reflect what he had listed… I have to re-examine that, only I need to read both chapters thoroughly!

That is what I get for doing something on the spur of the moment while watching TV!

If anyone is interested:

Cell Name - Input

Wg =           Weight of Fiream – pounds

W1gr =        Weight of Bullet – grains

W2gr =        Weight of powder – grains

Vp =            Muzzle Velocity – fps

Vc =            *Powder Charge Velocity - fps

Recoil Velocity =(((W1gr/7000)*Vp)+(Vc*(W2gr/7000)))/Wg

Recoil Energy =(((W1gr/7000)*Vp)+(Vc*(W2gr/7000)))^2/(64.348*Wg)

*I am using 4,700 fps constant for Powder charge velocity at the moment. (this is one area I am still researching.)