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1. It is best to use an additional formula to compare penetration.

2. The best three formulas are in my opinion Hatchers RSP Taylor's TKO and Thorniley used on this site.

3. No effort to take explosive wounding or bullet tumbling into account has been made in any formula I have come across.

The A square penetration formula is good for comparing penetration. Formula (.01 x Energy x Sectional density) divided by the area of the caliber. Note a rating of less than 85 is not recommended for head shots on Elephant.

A criticism of Taylor and others is a baseball is rated higher than an elephant gun. The penetration formula gives .14 for a 12 ft/lb air rifle which might penetrate about half an inch of flesh. The baseball at 118ft/lbs rates .086, it might be safe to say a rating of more than 1 is dangerous for humans.

Baseballs are not bullets but they are dangerous, otherwise catchers wouldn't need the protective gear they wear.

My formula is actually an add on to Hatchers. Hatcher's formula was meant for pistols. Lets look at three guns.

1 45 auto 880ft/sec 230gr bullet. 2. 30cal carbine. 1990ft/sec 110gr bullet 3. .223 armalite 3240ft/sec 55gr bullet.

The 223 is rated at 16.23 @ 0yds, 13.75 @ 100yds, 11.5 @ 200yds, and 9.55 @ 300yds.

The 30cal carbine at 32.92 @ 0yds, 25.68 @ 100yds, 20.24 @ 200yds and 16.97 @ 300yds.

The 45 auto at 65.56 @ 0yds, 60.7 @ 100yds

I have rated pointed jacketed bullets at 1050 instead of 900 for RNFMJ to allow for the fact that unstable bullets tend to tumble in flesh. The 223 still does not get to 30 which Hatcher considered the minimum to stop a man (>50 being recommended).

Next to allow for "Explosive Wounding" effect which requires supersonic speeds. The Mauser broom

handle was not noted for great stopping power with a Velocity of 1410ft/sec. Therefore I choose to use 1400ft/sec as the speed at which explosive wounding becomes noticeable.

With the velocities for the above ranges being 1840 more than muzzle velocity down to 506 more at 300yds for the 223.

Hatcher's formula is Energy/velocityx cal area x bullet factor (1050 for jacketed sharp bullets)

The area for .223 is 0.039, take 1840/10000 and add to caliber (0.407). the area for a caliber of .407 is 0.13.

The new rating for the 223 is 54.05 @ 0yds, 35.42 @ 100yds, 22.8 @ 200yds, 14.38 @ 300yds

The rating for the 30cal is 46.74 @ 0yds, 28.85 @ 100yds, 20.24 @ 200yds 16.97 @ 300yds.

I think this formula better reflects the reputations of the guns concerned. Note Larger caliber weapons like the 308 Winchester are not transformed into wonder guns by this formula, much of the increase in rating is lost after the first 100yds.

I hope this formula meets with the approval of the experienced hunters who use this site.

EDDIT this should have been part of the original post

There is a work on the net entitled "Shooting holes in wounding theories" while I don't disagree with much of what is written there the author has chosen to both remain anonymous and has not attempted to offer any thing better.