13 January 2018

In A Vacuum Made Of Spherical Cows

There are many methods of "determining" how effective your ammunition is going to be without even loading a round, let alone firing one.

Some correlate well with actual wounds, some do not.

Some correlate until the edges are approached.

Some are more tied to the rules of a competition.

Some are abstractly tied to the rules of a game where no guns are actually fired.

You almost have to delve into the history of the tests to see how they relate to real world performance.

You've got to see what proxies are in play.


  1. The Taylor Knockdown Formula is essentially useless for comparing anything except big bore Safari Rifles.

    The "Major Power Factor" and "Minor Power Factor" is useless except for competing in USPSA.

    All of these formulas focus on "internal ballistics" that produce a velocity/energy/momentum state of the bullet on leaving the muzzle. None of them focus on terminal ballistics.

    Does the terminal velocity retain enough energy to do the job? That's a pretty binary yes/no type answer. It is why the "25 to the back of the head" is recognized as a lethal shot while the "9mm to the knee" or "50 cal to the foot" isn't.

    I have yet to see any serious range limitations on bullets except for the military (when does velocity drop below bullet fragmentation/deformation energy levels) and hunters (when will this bullet completely destroy itself from too much impact velocity to when will this bullet not expand at all from too little velocity). Where rifle shooters can measure those in hundreds of yards, pistol shooters are generally not. But still, it's all academic until you pull the trigger.

    1. GURPS numbers are completely useless except for playing a role playing game...


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