"Barsness's Index":
I Believe That John Barsness Stands-Head-And-Shoulders-Above All Scientists In History Who've Devised Recoil-Calculation Formulas For Firearms. By Inclusion Of What He Labels The "Rocket Factor" He Takes Into Account Every Possible Factor Involved In The Equation. I Myself Remember Having Fired Old Winchester Model 70 Bolt-Action Rifles Chambered In .243 & .308 Calibers With A Wide Variety Of Experimental Loads Back In The 1970s. Loads With 100-110 Gr. Bullets And Near Identical Powder Charges Always Seemed To Pack A Bit More Punch-On-The-Jaw In .243 Than .308(The Cases Are Indentical Except For The .243's Smaller Neck Diameter). He Must Be Right-On-Target When He States That There's An Additional-Effect Generated When The Propellant-Gasses Are Screaming-Out-Of The Case Though A Constricted-Vent(The Case Mouth).