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Power Factor https://en.wikipedia.org/wiki/Power_factor_(shooting_sports) is an interesting attempt to quantify the relative power of different calibers and loads. Personally, my edc is Ruger P85 with full (16lbs versus factory 11lbs) extra power Wolff Combat recoil spring. I load a Hornady XTP 147gr BTJHP (that's right, it's got a bit of a boat tail) on top of 5.7 gr of Alliant Power Pistol. It's got a PF of 161((weight of bullet in grains x velocity)/1000; (147 x 1095)/1000 = 160.95) It is an outstanding performer.
Power factor is a simple formula, and notice it doesn't use caliber so it's concentrated on mass and energy. Could a better system be developed? Probably, but this is simple, and muzzle velocity is greatly affected by muzzle length; I've seen data suggesting that rifle barrels, from carbine to regular lengths, can have an average of 50fps gain/loss per inch. For comparison, my 44Mag load of a 300 gr. XTP on top of 19gr. of H110/W296, when fired out of my 7.5" SBH has a velocity of 1325 fps, and gives a power factor of 398. Same round, out of my Marlin 1894, has a PF of 489, with it's velocity clocked at 1625 fps.
Anyway, something to think about. And none of if matters if you don't practice!
Afterthought: the FBI data on terminal ballistics tests says something about an effective person stopper bullet should have a minimum 0.5 expansion (for example, a qualifying 9mm round would expand to be .53 inch (0.355 x 1.5 = 0.5325). In my own recovery of a +P 124 gr. Golden Saber, it measured 0.8 over nominal caliber, that is 0.63 inch.
2nd afterthought: since the power factor doesn't include terminal ballistics and type of bullet, the addition of another factor to the equation might create a good reference number for actual terminal perfomance so to be useful beyond 'knocking down pins'. In that vein of thought, maybe a factor that is a constant in hydro-static shock and penetration. I never made calculus in highschool, so I'm out of my league at this point but maybe someone would have a better understanding.
So much for not getting too scientific, as the O.P. was trying to avoid
Power factor is a simple formula, and notice it doesn't use caliber so it's concentrated on mass and energy. Could a better system be developed? Probably, but this is simple, and muzzle velocity is greatly affected by muzzle length; I've seen data suggesting that rifle barrels, from carbine to regular lengths, can have an average of 50fps gain/loss per inch. For comparison, my 44Mag load of a 300 gr. XTP on top of 19gr. of H110/W296, when fired out of my 7.5" SBH has a velocity of 1325 fps, and gives a power factor of 398. Same round, out of my Marlin 1894, has a PF of 489, with it's velocity clocked at 1625 fps.
Anyway, something to think about. And none of if matters if you don't practice!
Afterthought: the FBI data on terminal ballistics tests says something about an effective person stopper bullet should have a minimum 0.5 expansion (for example, a qualifying 9mm round would expand to be .53 inch (0.355 x 1.5 = 0.5325). In my own recovery of a +P 124 gr. Golden Saber, it measured 0.8 over nominal caliber, that is 0.63 inch.
2nd afterthought: since the power factor doesn't include terminal ballistics and type of bullet, the addition of another factor to the equation might create a good reference number for actual terminal perfomance so to be useful beyond 'knocking down pins'. In that vein of thought, maybe a factor that is a constant in hydro-static shock and penetration. I never made calculus in highschool, so I'm out of my league at this point but maybe someone would have a better understanding.
So much for not getting too scientific, as the O.P. was trying to avoid
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