[mikmarandola]

I have research into stopping power fomulas. hear are my conclusions.

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.

 

[MikeG]

Welcome.

Good luck with your quest. I have hunted enough to absolutely doubt any formulas as being the least bit predictive of what will happen when the trigger is pulled. But that's just my opinion and experience.

 

[kdub]

+1, Mike. Best advice is to get a well constructed bullet for the game intended and don't run it either too slow or too high velocity. Placement, placement, placement.

 

[shane256]

I just saw this site and thought of this thread: http://www.rathcoombe.net/sci-tech/ballistics/wounding.html

 

[dougw47]

ballistics

Wow, shane...I read myself cross-eyed on that site.

 

[broom_jm]

Sheer poppycock! Hit 'em where they live, with a decent bullet. Done and done.

 

[Saskshooter]

All attempts to make a mathematical formula for how animals die is doomed to failure. Go shoot some things and you will realize that.

 

[mikmarandola]

15% rule

If you don't like to use stopping power as a guide to choosing the right rifle for the job fine. but don't dismiss something as rubbish without giving a reason. I suspect some people who do this have a dislike for or find maths difficult and tiresome. Terminal ballistics is not an easy subject to get your head around. The point is to use maths to model what happens in reality. You don't necessarily need a formula which looks like its rocket science.

This is a fact not to do with ballistics There is about a 15% chance that any bullet big or small will strike somewhere on the human body which will cause instant incapacitation. Assuming an animals body is similar a 22 bullet is as likely to kill an Elephant as me. with an Elephant that means through the eye at the right angel to hit the brain. I think the chances of pulling that off are very poor indeed. A 22 long rifle has little chance of penetration except in an Elephants eyeball.

To improve the chances of getting the desired effect surely everyone can see what is needed is faster heavier bullets of larger caliber bullets must have enough energy to reach an animals vitals. Large calibers require more energy to do that but they do make a bigger wound channel.

 

[broom_jm]

Mik,

You really need to get your head out of the textbooks and into a camo baseball cap, so you can hit the woods. What you are studiously ignoring is that you clearly have little, if any, big game hunting experience. All the formulas are just frivolous massaging of numbers, whereas actual time in the field will teach you lessons you can never, ever explain, or learn any other way.

Why does a deer with a sizable hole through its heart, and lungs that resemble pate, run 150 yards? How is this even possible, when the "formula" says you did everything right and that deer should have died, on the spot? By the same token, why do some cartridges with quite modest "numbers" seem to kill big game with stunning alacrity, while more powerful rounds in the same caliber are sometimes observed to dispatch game in less-than-spectacular fashion?

I've read the books and done the math, but that was long ago, when I was young and impressionable about such things. None of the numbers you can quote mean anything, as compared to the very simple truth of the matter:

Bullets kill by penetrating, expanding, and (hopefully) exiting, after hitting precisely where you aimed. Within reasonable limits, the diameter, mass, sectional density and velocity of the projectile ARE COMPLETELY IMMATERIAL. Talk to enough guys who have harvested a lot of game, or get out there and do it yourself, and you will come to understand these things. Formulas and equations will cease to have much meaning, where big game bullet performance is concerned.

 

[mikmarandola]

Jm.,
Let me say I have done no Big game hunting, and I am ashamed of any hunting in which I have been involved. I am not going to bang on about hunting ethics, but (I think) all wild animals are property of the crown. Making it illegal to shoot swans for instance.

Let me rather talk of the hunting I have seen. Rats Mice, and birds of starling size. All have went down instantly with an air rifle of 11 foot pounds energy and 16.5 grain pellet. The nearest to an escape was made by a rat which managed about 2 feet. None of this proves anything but of the 20+ formulas I looked at this rifle never made it on the bottom rung.

When I was a boy my mothers friend had a cat which was shot with a similar rifle about 5 times. I am glad to say the cat recovered and its owner thought the money on vet bills well spent. A deer running at only 15mph would cover 150yards in about 20 seconds I don't think that is a bad result.

Your last post has left me with no real arguments left to make, except perhaps this one. If a modest rifle will do the job and a superior one cannot be relied on, you may as well carry the modest rifle. I think a close encounter with a bear instead of a deer may change your mind back again.

I suppose what I am trying to say is how do you make sensible choices.

Thanks to all of you who made replies my only disappointment is that it seems those who like stopping power formulas are out numbered by those who don.t.

PS why have these posts been moved and to where.
mik

 

[varminter]

If I were thinking about buying a rifle I would rather talk to someone who can show me the math but more importantly can tell me from experience how that cartridge will perform. If I ask, "In your experience How does the .300 WSM perform on a mature Bull elk?" and he said "well I don't hunt but I shot a rat with an air rifle and it died on the spot." I would immediatly discount all information he has given me and go find a hunter to talk to.

A physicist can explain how a martial arts master can generate enough power to stop a human heart with one strike. He however cannot teach that technique.

 

[mikmarandola]

Varminter
Thank you for your reply. It made me smile. Anyone who reads your post will think me a clown. Oh well never mind perhaps I am.. I do see the point you are making (the reason for my smile). Your reply suggests you know something of martial arts.

I am a martial arts expert I have studied Karate, Judo and Jujitsu, and done a very little Kendo. I used to teach Judo and Jujitsu untill I became ill about 8 - 10 years ago. Said illness has caused my retirement and left me disabled which has nothing to do with anything except that I can no longer teach.

Perhaps my attitudes have become a bit Oriental I don't know. As a retired engineer I study interesting things like aircraft, History, weapons, etc because I am bored out of my skull.

I don't want to kill you (or anyone else) but I do want to know how to.

 

[varminter]

I understand. nothing to do but math. I don't mean to make you out to be a clown. your mathmatical skills far surpass my wildest dreams. I am he who finds math to be difficult and tiresome. I suppose we have made our points. Don't let all of the arguments on this thread discourage you from posting here. Without debate, the ideas that changed this world may very well never been thought of. The ideas and input from engineers have made this forum one of the most informative I have ever come across. I would hate to lose one because of argumentative postings. Most people here mean well and the moderators remove the ones that don't very quickly.

Yes I have some martial arts experience. Aikido and six years of Kempo. also, I too dabbled in kendo but not very seriously. sorry to hear you can no longer train. I guess we should be grateful for what we have.

keep posting. An idea that starts an argument isn't always a bad idea.

 

[mikmarandola]

Pearls of wisdom

A wise man (at least I thought he was wise) once told me.

A quarrel is an argument went wrong, liable to excite spontaneous unnecessary violence. He followed with this advice.
Learn to argue do it well, but remember when you get better at it than me it doesn't make you right.

I do enjoy a good argument/debate. I actually learn a bit from the posts on this sight.

mik