Nolo's thread about up-loading .45 ACP got me thinking about the different measures people use as surrogates for the effectiveness of a handgun round in wounding/incapacitating an assailant.
It seems to me that there are several factors that play in to this. There are also a number of different measures or statistics people use to quantify these factors.
I thought I'd try to catalog them, along with the advantages and disadvantages of each measure.
Permanent wound channel: A function of penetration and the (expanded) diameter of the projectile. Measured under controlled laboratory conditions (ie, shooting tissue simulating gel).
Advantages: Most of the more scientific ballistics gurus tend to emphasize physical damage to vital organs as the most reliable/effective mechanism of wounding from handgun shootings. Permanent wound channel seems like it would reflect the ability of a handgun round to damage vital organs.
Disadvantages: uncertain what extent ballistic gel accurately simulates human tissue - invites the question whether or not these measures reflect real world shootings. Testing is expensive, and not all loadings have been tested or tested thoroughly.
Kinetic Energy: Calculated from the mass and velocity of the projectile.
Advantages: Easy to calculate; produces a single number that is easy to compare between calibers/loadings.
Disadvantages: Not clear to what extent greater energy translates into greater wounding/incapacitation effectiveness: does more energy create effects simply via penetration and expansion? Or does energy have effects beyond the physical destruction of tissue? Formulas may exaggerate the effectiveness of lighter, higher velocity projectiles since velocity increases energy geometrically while mass increases energy arithmetically.
Sectional Density: Calculated from the cross-sectional area and mass of the projectile
Advantages: Easily calculated and compared. Thought to be the main determinant of penetration.
Disadvantages: Doesn't take into account velocity, which also influences penetration. May exaggerate the effectiveness of heavier bullets given the same caliber (ie; 147 grain 9mm vs. 115 grain 9mm).
Street Results: Data gathered from actual shootings and/or autopsy results
Advantages: reflects real world performance
Disadvantages: Newer or more unusual calibers are not well represented (fewer shootings = smaller sample). Data usually is not collected or analyzed in a controlled systematic way, so conclusions are not scientifically reliable.
I know there are some others... what do you use to compare the expected performance of different calibers and why do you rely on that measure?
It seems to me that there are several factors that play in to this. There are also a number of different measures or statistics people use to quantify these factors.
I thought I'd try to catalog them, along with the advantages and disadvantages of each measure.
Permanent wound channel: A function of penetration and the (expanded) diameter of the projectile. Measured under controlled laboratory conditions (ie, shooting tissue simulating gel).
Advantages: Most of the more scientific ballistics gurus tend to emphasize physical damage to vital organs as the most reliable/effective mechanism of wounding from handgun shootings. Permanent wound channel seems like it would reflect the ability of a handgun round to damage vital organs.
Disadvantages: uncertain what extent ballistic gel accurately simulates human tissue - invites the question whether or not these measures reflect real world shootings. Testing is expensive, and not all loadings have been tested or tested thoroughly.
Kinetic Energy: Calculated from the mass and velocity of the projectile.
Advantages: Easy to calculate; produces a single number that is easy to compare between calibers/loadings.
Disadvantages: Not clear to what extent greater energy translates into greater wounding/incapacitation effectiveness: does more energy create effects simply via penetration and expansion? Or does energy have effects beyond the physical destruction of tissue? Formulas may exaggerate the effectiveness of lighter, higher velocity projectiles since velocity increases energy geometrically while mass increases energy arithmetically.
Sectional Density: Calculated from the cross-sectional area and mass of the projectile
Advantages: Easily calculated and compared. Thought to be the main determinant of penetration.
Disadvantages: Doesn't take into account velocity, which also influences penetration. May exaggerate the effectiveness of heavier bullets given the same caliber (ie; 147 grain 9mm vs. 115 grain 9mm).
Street Results: Data gathered from actual shootings and/or autopsy results
Advantages: reflects real world performance
Disadvantages: Newer or more unusual calibers are not well represented (fewer shootings = smaller sample). Data usually is not collected or analyzed in a controlled systematic way, so conclusions are not scientifically reliable.
I know there are some others... what do you use to compare the expected performance of different calibers and why do you rely on that measure?