I am on my way to Botswana soon. The topic of lethality indices for big game rifles is a topic well suited to BS. The BSI or Bwana Saeed Index is not BS.

My credentials: I own and reload for and shoot fifty rifles from .22 to 50 BMG. I started shooting with a 12 guage shotgun when I was eight years old. I have hunted and killed numerous heads of game in North America from Alaska to Tennessee, including deer, sheep, goat, caribou, moose, bear, boar, and two feral water buffalo, the largest of which was estimated to be 1800 to 2000 pounds. I have always dissected the game to observe bullet performance and retreive bullets if they didn't exit. I have also taken Russian wild boar solely with a spear (it charged right onto the spear I held as I approached) as well as other boar with rifle and handgun, and deer with handgun. I have shot deer with the .223 through the .458. I also found Mitch's .577 Tyrannosaur enjoyable to shoot. I was also the only plebe in my company at West Point to make expert with the rifle in 1972. I dropped out of there when they dropped out of Viet Nam. I am thus a "Viet Nam era veteran" who later served four years as an Air Force Captain.
This should vouch for my familiarity with weapons, especially hunting rifles and their effects on game.

I studied chemical engineering prior to going to medical school, hence had courses in metallurgy, thermodynamics, statics and dynamics, fluid mechanics, circuits, statistics, and lots of higher math, physics, chemistry, and the more esoteric courses like "staged mass transfer," lots of biology and the impossible to master field of medicine. I also have a university degree in accounting, a business degree for my own edification. Surely this should indicate that I am not a blithering idiot.

The Bwana Saeed Index is a simple method of evaluating a hunting rifle's effectiveness with either soft or solid, though the hunter must be wise enough to select the properly constructed bullet.

BS = Big Stick Factor

BSI = BS X 100 = Bwana Saeed Index

BS = (C)(W)(V)(S)/(7000)(12)

C = caliber, inches
W = bullet weight, grains
V = velocity, feet per second
S = sectional density, conventional
7000 = 7000 grains per pound
12 = 12 inches per foot

Thus:
BS = CWVS/84000
Or:
BSI = CWVS/840

It is remarkable that the BS of the .375 caliber 300 grain bullet at 2450 fps (sectional density = .305) calculates out to 1.00 exactly. This is a unitless number by its derivation from the unitless sectional density number. The BSI is therefore 100, and this is by definition the minimum African dangerous game/true hunting rifle BSI, because it meets the legal requirements for bore size and kinetic energy (4000 ft.lbs. exactly!) and is the common wisdom of the .375 H&H minimum effective load. This is real, not imaginary.

Saint Finn Aagaard said a .458 caliber 500 grain bullet at 2150 fps (sectional density .341) was a good stopping rifle. Remarkably the BS = 2.00 exactly, and the BSI is therefore 200 for this load.

Another remarkable fact is that the .577 Tyrannosaur has a BSI of exactly 400 when the .585 caliber 750 grain bullet is loaded to 2447 fps (sectional density .313). This would generally be accepted as more than enough whomp. This is where stopping rifle ends and dinosaur rifle begins. Thus the velocity of the T. rex should be kept below this number for practicality.

Thus we can class the hunting rifle for Africa by BSI levels as follows:

LR light rifle, for non-dangerous, thin-skinned game: less than 100 BSI

TR true hunting rifle, for big five and lesser game: 100 to 199 BSI

SR stopping rifle, for backup situations: 200 to 399 BSI

DR dinosaur rifle, for stunt purposes: 400 BSI and up

More discussion will be presented in the Accurate Reloading Africa Book.

There is no better way of quickly and easily ranking the effectiveness of the big bores.

The Taylor KOV would give inordinate numbers to a Frisbee. The Bekker KOV and Alphin PI would make out a needle to be the ultimate killer. The BSI tells the story properly.

Those who bicker about momentum versus kinetic energy are not seeing the forest for the trees. A bullet's kinetic energy is determined by it's momentum, whether angular or translational. Kinetic energy is calculated from mass and velocity and that is momentum as its basis.

Those who bicker about the cross-sectional area are ignoring the fact that this is simply a function of bullet diameter.

This myopia arises from a desire to be strictly scientific and have a formula that calculates a number with units defined by physics, and to have this number correlate perfectly with bullet performance on some model that represents the game animal. Well, this is impossible. The squabblers should consider this fact and accept the best tool available for the real world (the Bwana Saeed Index of course) or stick to theoretical models only, and shoot the bull forever over this topic.

The BSI is only an approximation, but is the closest to reality that I know of. If anyone knows of anything better, let me know.

When you involve our convention of sectional density you are already unit-less. Charging blocks of gelatin are not runaway cape buffalo.

Yes the BSI says the 350 grain .375 is a better killer, and so would be the 450 grain .416. Read the Accurate Reloading Africa Book if you care for some more examples.

Calculate some BSI numbers yourself if you want to know how your pet cartridge stacks up.

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Good huntin' and shootin',
Bwanawannabe, Daktari Ron

[This message has been edited by R. A. Berry (edited 05-06-2001).]

Huh?

I hope the buff and ele know what they're in for.

No debate? Can't someone give me a little verbal sparring over this? Is it irrefutable? Of course it is not of earth shaking importance, but it is good at what it is meant to do: rank the big bores better than the Taylor KO values, or anything else out there.

------------------
Good huntin' and shootin',
Bwanawannabe, Daktari Ron

Dok,

I like known formulas and measuring things to the Nth degree. Unfortunately performance on game is not all that predictable. I know muzzle energy alone is not a good measure of performance. There my surety stops when it comes to simple formulas.

Don

Rab, Excellent treatise on stopping power. I do think that there is a temptation to worship at the alter of pure numbers, whether it be KE, momentum, etc. It must be remembered that the damage is done by the bullet's ultimate interaction with the animal. Example: you shoot a buffalo in the shoulder with a .378 Wby, 270 grain Hornady bullet (impact velocity 3100fps) and KE about 6000fp. The bullet disintegrates upon impact and nothing reaches the vitals and you have one mad buffalo. If you had a well-built 350 grain bullet at, say, 2700fps it penegrates and kills promptly. In both cases the animal received about the same energy but the effects are different. When the bullet disintegrated it spread the energy over so large an area there was no penetration. (It should be noted that the recoiling rifle actually departs more energy on the shooter's shoulder than the animal receives. That energy is spread out over space and time--that is why we aren't killed when we shoot.)

I've always found it interesting that the visible hole left in a small animal shot with a large rifle is so much greater than on a small one. I've taken a .416 Wby with factory swifts to Africa twice. On small animals it would leave a huge exit (about 5" across on warthog, gerenuk,etc.) but seem to do much less damage on buffalo. Example: I hit a buffalo on the shoulder angling backwards. The entrance wound on the ribcage was only about 3/4". The bullet did a fair amount of damage to the lungs and great vessels but the effect was nothing like that seen on smaller game. The reason for this is that the buffalo's shoulder can take up a lot of energy with little effect. By the time the bullet entered the chest cage it had fully expanded and lost a lot of velocity.

Kinetic energy is probably a more valid indicator of killing power in smaller game. Unfortunately, when we discuss it in regards to Africa it is usually in regards to buffalo, elephant, etc..

I think that this partly explains why you won't see many Ph's carrying .378's and the like. I was always a velociphile until I started hunting in Africa about 12 years ago. The more I've seen it seems to me that the old PH's weren't really that stupid after all.

Rab, please share the details of the Botswana hunt. Where, who with, what for, etc. I'm jealous.

RA,
Can't let you sally forth to Africa, quite so easy....

Formulas are formulas and thats about as far as they go...They never take into account secondary missles re: bone fragments and bullet fragments and the other indicators of sudden death syndrom.

Taylors formula is sure enoungh correct based on solids, which it is, by the way..How he figgured it who knows? Mathimatical gibberish, thats what formulars are about, but actual experience says they are very near correct and I suspect yours is too...Mostly formulas entertain theoretical minds I suspect. Most gun nuts is plumb et up with theory. If it satisfys ones mind and creates euphoria then who can condem it.

On the other hand common since, is the best formula for the killing power of big bores, the Atkinson formula is: The big dog gets the bone and sleeps on the poarch....

------------------
Ray Atkinson

ray@atkinsonhunting.com
atkinsonhunting.com

RAB,

I think any of these formulas need to have a factor entered for energy otherwise the "frisbee" will appear. I just did a quick check and your formula is giving about the same index for a 70 caliber 1000 grain bullet doing 400 f/s as the 375.

I have shot tons of small animals nut no big ones so I have to theorise on big ones.

However one thing is certain and that is our rifles are very small on big animals as compared to the smaller animals. Comparing calibers with bullets from 300 to 600 grains on very big animals (say buffalo) is like comparing bullets of from 30 to 60 grains at 2000 to 2500 on deer or pig size animals.

Bullet placement and adequate penetration will be the key factors, when the caliber is very samll for the animal size.

On smaller animals, the observation I have made over the years and on literally thousands of animals is that is the bullet expands correctly and the velocity is around 2000 f/s or more, then if energy is about the same the bigger bullet with more momentum is the deadliest. This is very evident when comparing a 300 Winchester with light bullets and a 458 with 400 Grain Speer flat nose at 2000 to 2100 f/s.

JohnDL has mentioned a point that is worth expanding on when he compares buffalo to smaller animals. Impact velocity does not matter so much. What matters is velocity during penetration. For example, a 300 Hornady round nose in 375 will be travelling much faster "through" a deer size animal than will a 100 grain 270.

As I remember John Taylors formula was for solids only and for elephant head shots. If one thinks about it such a formula probably has some application in this area.

However, apart from the elephant head shots, I think formulas will only really apply on smaller animals. Perhaps animals to 1000 pounds.

My observation leads me to believe that a formual should cated for a few velocity "brackets".

I would put these at about 1200, 2000 and 2500 and above.

Bullets at 2000 seenm dramaticallyu more powerful than 1200. Likewise for 2500 and above compared to 2000.

As a minature example one only need look at the 22 rimfire, 22 rimfire magnum and the 22 hornet and 218 Bee.

Velocities much above 2500 don't seem to make any difference and if anything are not as good. Assuming of course correct bullet expansion.

So in summary my formula would be something like

Energy X Momentum X Velocity Factor X Caliber

To this I would also add X Point Shape Factor

But I don't know what number could be used for spitzer, semi spitzer, round nose and flat nose. But the number would be lowest for spitzer and highest for flat nose.

JohnDL's example on buffalo and small game with his 416 Wby I think illustrates momentum in action, especially on smaller animals.

A bullet with more momentum must move either more flesh at the same speed as a bullet with less momentum or the same amount of flesh at greater speed than the smaller bullet.

Mike

[This message has been edited by Mike375 (edited 05-06-2001).]

All these indices are overrated or misinterpreted, esp. when expressions are used like "killing power".
Some are useless, some are only meaningful if limited to a small range of caliber, weight etc. But than we can also judge from our experience. A bigger bore with near the same velocity is better than the small bore......and so on. But that stops if you try to outweight a 1000 gr at 400 f/s to a .375 at normal velocities.
Alphin�s PI is only used to have an impression on the penetration of solids. Nothing more. Not its interaction with the animal. Not the killing power of a needle.
A .458 500 gr with a velocity difference of 150 f/s to a 550 gr gives a BSI difference of about 10 %. Do we detect that in reality?
BSI may be the best interpretation of numbers from exterior ballistics. Even when we choose the proper bullets, we don�t know exactly what is to happen in the animal. We need in addition a BPI (bullet performance index). And what about an API (animal performance index)? Some animals seem to withstand our theories. Not to speak about a HPI (hunters performance index).

RAB,
Pls help: Why is SD unitless? Weight per area of a moving bullet is equivalent to pressure. The BSI has the dimension of mass squared per second?

------------------

RAB --
Well, I lack your credentials, having hunted less and spent far less time in the classroom. On the other hand, I went to Annapolis, which all would agree, means that hour for hour my education was superior! But you do get credit for leaving even if you did put on the bus drivers' uniform to cruise "The Wild Blue Yonder"! (winkin' an' grinnin', here)
It would seem to me, caliber should be accounted for beyond sectional density, in that the area of severed and bleeding tissue is proportionate (ignoring hydrostatic shock and bullet deformatiom and construction )to the circumference of the projectile. In other words, to put it in West Point engineering lingo, fatter bullets punch bigger holes.
Good luck in Botswana.
BEAT ARMY!
-- Doc

To All:

Some very good responses, and nothing that contradicts the new accounting method for big bore performance: The Bwana Saeed Index.

The BSI is a gun nut thing, so if it is too tedious for anyone, no worries. We must give old John Taylor credit for coming up with the basic concept of ranking the big bores. He was the grand daddy of gun nuts, and died in obscurity. So the BSI is for fun mainly, but undeniably the best thing going for ranking the big bores, in memory of John Taylor and in honor of Bwana Saeed for making this exchange possible.

The BSI is nothing more than the Taylor KO (TKO) value modified for unitary consistency and augmented with a sectional density term.

The TKO included a correction for grains to pounds (7000) but did not bother with inches to feet. I threw in the 12 term in the denominator. Then the sectional density factor was added. The 100X factor was added last to convert 1.00 to 100 to do away with decimals and create the final version called the Bwana Saeed Index, or BSI.

Actually, if we were dealing with bullets of only one specified sectional density, the BSI and TKO values would be equivalent, or directly proportional between their two different scales.

The BSI penalizes for sectional density decrease and rewards for sectional density increase. The TKO is oblivious to sectional density.

Remember that the BSI is meant for use on existing sporting loads at the practical velocities and calibers and bullet weights that are used to hunt game. It is not meant to rank rocks or spears thrown by hand.

Remember that it says nothing about bullet construction. It is useful on softs and solids at close range. The hunter's knowledge of the animal, the projectile performance, stalking skills, bullet placement, and animal reaction are what is hard to quantify. The BSI or any index is only equivalent to ranking the booster rocket that delivers the payload. It says nothing about the guidance system or payload nature.

Being a gun nut and a numerical/spatial kind of guy rather than the intuitive/verbal type that most women tend to be, the idea of an index with numbers appeals to me. When one plays with as many guns as I do it is fun to quantify one aspect of their performance: BSI.

------------------
Good huntin' and shootin',
Bwanawannabe, Daktari Ron

Will,
No ele on the agenda, just buff, kudu, impala, warthog, and wildebeest, if that is how you spell it.

------------------
Good huntin' and shootin',
Bwanawannabe, Daktari Ron

Don G,
You sound like a reasonable guy to me. The BSI is a reasonable guy thing.

------------------
Good huntin' and shootin',
Bwanawannabe, Daktari Ron

JohnDL,
You sound like a reasonable guy too. Actually the above was more a treatise on myself to seek credibility for the Bwana Saeed Index. All that you have said is supportive of the BSI by my interpretation. Thank you.

Oh yeah, Botswana will be with the "Africa Wild" outfit owned by the McFarlane family, plains game in the southeast, and buffalo in the Okavango area. I will surely tell the details afterwards, but a bit late now to worry about getting any other info now. I hope to meet some real bushmen while there. You know, the gods must be crazy.
------------------
Good huntin' and shootin',
Bwanawannabe, Daktari Ron

[This message has been edited by R. A. Berry (edited 05-07-2001).]

Ray,
Thank you for your support of the Bwana Saeed Index. All that you have ever said about guns and loads is backed up by the BSI. I always read your posts, for fun and information. You have actually contributed to BSI nomenclature. "Whomp" is what the BSI measures, to put it simply.

------------------
Good huntin' and shootin',
Bwanawannabe, Daktari Ron

Mike375,
The .700 caliber 1000 grain bullet has a sectional density of 0.292. Even at only 400 fps it would be pretty formidable to take in the chest if it were a spitzer solid. About the same as a 12 guage slug in diameter but more than twice as heavy and less than a third as fast. Compare it to the .375 300 grain bullet at 2500 fps with sectional density of .305:

.700 cal: TKO = 40.0 BSI = 97.3
.375 cal: TKO = 40.1 BSI = 102

This makes for an interesting comparison. The BSI does show that the .375 would be slightly superior to the odd ball projectile, and by chance the TKO for the two projectiles is almost identical. I think the BSI is closer to reality. Actual test firing would have to be done to see which did what better. To me it seems the BSI is more believable: anyway you slice the loaf it stacks up better.

As for your suggested formula, you must be kidding, pulling my leg, yanking my chain. Kinetic Energy X Momentum = (1/2)MV*2 X MV
This is velocity cubed. And setting up velocity parameters to apply a fourth velocity term to the cubed one would be so complicated as to be likely impractical.

I am suggesting a practical index easily applied to guns actually seeing use in the field. I appreciate your clowning around with the velocity to the Nth power, however, LOL.

------------------
Good huntin' and shootin',
Bwanawannabe, Daktari Ron

Norbert,
Are you bull shitting? The new and improved Norbert now allows even himself to make a joke?

Sectional density is unitless, as any authority will tell you, because it is artificially contrived or defined as follows:

Sectional density = (bullet weight in pounds) / (bullet diameter in inches)*2

That is, square the bullet diameter and divide it into the bullet weight.

This is not the bullet weight per cross-sectional area of the bullet, which would be necessary to have actual pounds per foot squared. The pi-r-squared formula is not used to calculate the bullet CSA in the conventionally defined sectional density number.

It is valid however, because the CSA is directly proportional to the diameter squared of the bullet. Sectional density is a valid ratio for comparing bullet weight per cross-sectional area between two bullets, but the actual units of the sectional density are meaningless.

As for your other indices, keep working on them. The Bwana Saeed Index was the easy part of the equation.
Best Regards,

------------------
Good huntin' and shootin',
Bwanawannabe, Daktari Ron

[This message has been edited by R. A. Berry (edited 05-07-2001).]

DOC GARNETT,
GO NAVY! You are right about West Point. BTW I did attend the Army-Navy game in Philadelphia (JFK Stadium) in 1972. Football. Navy won.

The BSI gives equal credit for caliber and sectional density. You should too.

------------------
Good huntin' and shootin',
Bwanawannabe, Daktari Ron

RAB,

I was not clowning around.

My obervation has been that if energy is similar the bullet with more momentum (assuming correct expansion) is more destructive on "soft" targets.

If we took a 458 with a 400 grain at 2000 that is 3550 ft/lbs. A 150 grain in a 300 Winchester would have do 3265 f/s to get the same energy. However the the 458 load has 63% more momentum. My observation has been that with such loads the 458 is far more destructive on "soft" targets.

On the other hand the 458 400 grain at 1225 f/s would have the same momentum as the 150 at 3265 but its energy would be only 1330 ft/lbs. My observations shows this type of load in the 458 is less destructive on "soft" targets than a 300 Winchester 150 grain bullets.

What I am suggesting is that for animals up to perhaps 1000 pounds that energy be used as the base line and then momentum and probably caliber added in (or multiplied) to the equation.

As well, I suggested velocity "brakcts" as another factor. Once velocity seems to get above 2500 or 2800 there does not seem to be much if any increase in destructive power, excepting on steel and other non animal type materials.

Unfortuantely my experience on animals is limited to the kangaroos, pig and goat. However I have shot these in the 1000s and since I was 15. Am now 53. Thus I have seen a wide range of components and variations in the same bullets.

It is that experience plus other testing that has led me to to the 2500 to 2800 velocity.

Whether that translates to other animals I do not know. However, it is interesting than in their repective caliber areas (small and large)the 30/06 and 375 seem to have totally dominated and of course they both operate in this velocity bracket.

As you have noted yourself, the BSI is John Taylors forumula with SD added in. But his formula was for solids and head shots on elephants.

I am trying to suggest something for the animal under 1000 pounds, which probably represents 99.9% of all animals shot.

Mike

Mike,

I once proposed the rule that "as long as energy in ft lbs /animal weight is bigger than 4 , energy is enough." I then saw my brother's shoulder shot on a young mulie with a 180 NosBT at 3000 fps. The animal died, and immediately, but we never knew why. The rib cage was not penetrated although the shoulder was gone - as if someone had scooped a serving-bowl sized chunk of meat out. After that I wanted to start adding bullet requirements, etc. It's just not simple, and you can never say never or always. (See, it's a trap!)

Don

Don,

In Australia up until about 1970, the 303/25, 303/270 and 218 Imp Bee on the Martine were very common calibers. Also used was the 303 with 140 soft point factory laods at about 2600. We also had a thing called a 7.7 X 54. This was a 303 witha very slightly shotened body. This was done to prevent chambering 303s as the 303 (or any military caliber) was illegal for a long time in different Australian states.

Then the 222, 243 and 270 started to go ahead.

Those who have extensivel used both sets of calibers (including myself) will tell tou that the 218, 303/25 and 303/270 were better killers than the other 3calibers.

The 303/25 had an 87 grain bullet at about 2700. In the 303 /270 the factory loads were alos about 2700 with 100 grains. We used to get about 2800 by necking down the Mark 7 303s and seating 100 grain bullets on the cordite load.

I could no even begin to count the number of kangaroos I have shot with the 270, 308 and 300 Winchester. The 308 is clearly superior.

Apart from 375s, 458s etc. and the like on roos, the only thing I have used that matched the 308 was the 303 with 140 soft points at 2600.

One other thinh that I think applies to killing power is caliber thresholds.

As an example I will use the 243 and 270. Anyone in Australia who has done a lot of shooting and over alot of years (varied components) will all tell you that the 270 is miles in front of the 243 and the 243 does not seem much different to the 222.

So there seems to be some threahold between the 243 and 270. Whether this applies to other animals I don't know. Perhaps it does with both the calibers and the animals scaled up.

On other thing which I find interesting on small Vs big and slower calibers. The 300 H&H never had the success of the 375.

Mike

Apart

OK guys, I don't pretend to the mathematical sophistication that would allow me to work out all this arcane ballistic detail. But if I might, let me ask a simple question about terminal ballistics; how large in weight and at what velocity would the projectile need to be going to be able to do to a buffalo what we do to prairie dogs routinely. Nothing more than a thirty inch back flip and a parting of the body roughly in the midsection. Or, if it's simpler, how much to just pop the head off and flip it a couple feet? And would the average PH think this was adequate?

------------------
If Elmer didn't say it, it probably ain't true.

Mike375,
I follow you, but you are getting too complicated and precise for my needs. I just want a rough rule of thumb that fairly closely approximates reality for the commonly used loads in the sporting field. That is the BSI.

------------------
Good huntin' and shootin',
Bwanawannabe, Daktari Ron

Just off the top of my head here, I'd be looking for a way to include bullet construction, which I think everyone agrees to is critically important.

Why not use bullet weight after penetration (retained weight) in the BSI formula? Then, a fragmenting bullet would create a near "0" value through the multiplication.

Similarly, I believe frontal area after expansion should be used, rather than before. Inherently, a bullet that expands to 2x caliber will do more damage than a solid that does not expand at all -- assuming full penetration of the animal.

Using expanded caliber requires the formula to account for bullet penetration, in %. Here, a bullet that penetrated 100% of the animal would retain 100% of the BSI value, whereas fragmenting bullets that barely break the skin would get, say, 5% of their BSI value.

I suppose it depends on how complicated the formula can be. FWIW, Dutch.

RAB -- Well, so much for the superior education! I SHOULD have said that acounting for caliber in addition to sectional density is necessary to account, however theoretically, for the area of severed tissue. SD "accounts" for the length of the "cylinder" in that it helps determine penetration. Caliber "accounts" for the circumference component of the area of the the theoretic, cylinder wall of the wound channel (exceptions noted in my previous post). Cross sectional area, again determined by caliber, is also a factor in the resulting shape of the hydrostatic shock path, which is an important component in the lethality of the wound.
In other words, the BSI, in the words of that renowned ballistician, Alfred E. Newman, "Makes sense to me." :-)

-- Doc

Im not sure how serious RAB was about the BSI. Maybe we are taking it too seriously?

Just the name has got to count for somehting.

If you do want a quick mathematical basis for determining some minimum acceptability for a specific species, I suggest:

Energy x Frontal area (not caliber!!!).

If you have the ability to measure penetration and expanded frontal area (not caliber!!!) then add the penetration and substitute expanded FA for unfired FA.

This way you can compare a soft to a FMJ.

This actually does work pretty well.

The BSI makes a 5.56 x 45mm look like a fly swatter that is only half as powerful as a 40 SW handgun ctg, which is a reliable base line for humans.

A 12 ga slug is over twice as effective a BSI as a 7.62 x 51mm (308 Nato) which just aint so. the 12 ga is also pretty close to a .375 which isnt so,

Like I said on the 350 gr 375 thread, dont use momentum theories to calculate killing power. Just does not model to reality.

RAB's idea of starting with the 375 as a baseline for large game is a very good idea though. You can use a 270 winchester for deer as a baseline. And the un-inspiring 458 for dangerous game if you like.

A 180 gr 40 SW works as baseline for two legged critters.

Andy

RAB,
Only for smokeless though. Look what happens when we work out figures for the heaviest bore rifles.
BSI
500 A-square (max) Approx 311
600 nitro Approx 435
4 bore Max 700+
2 bore Don't ask!!
At least the SD keeps them trimmed down a bit.The 8 bore seems to fit unlike in taylor's formula.

Karl.

[This message has been edited by Karl (edited 05-09-2001).]

The poor old bore rifles seem to be stuck with the rocks,frisbees and discus' when it comes to formulas.

Karl

had to edit, wrong smiley!

[This message has been edited by Karl (edited 05-09-2001).]

To all:
I like the discussion that this has generated. I was kept away for a couple of days by work. I really don't have the time or energy to haggle the fine points being made.

The BSI should be considered "A Modest Proposal" initially proposed on realizing the shortcomings of the Taylor KOV and its limited application only for brain shooting elephants with solid bullets.

The BSI is pseudo rocket science, but I truly believe it is suitable as a guide to rating the large bore rifles that operate with heavy bullets at moderate velocity. It even works pretty well at the extremes of velocity, caliber, and bullet weight, but should not be applied to varmint rifles or howitzers. It can be used for solids or softs at close range. Questions of killing power and bullet performance are left to the hunter to determine by artful selection of projectile construction used and shot placement. BSI is a measure of WHOMP that is more than just kinetic energy or Momentum.

Since it is calibrated to reflect some basic common sense in practical field application, it really should be satisfactory as a guide, IMHO, and FWIW, I don't think anyone has come up with anything better.

BTW, "whomp" is also that sweet sound heard after a solid hit on big game. It is the sound of bullet impact that you hear as the blast of the muzzle dies.

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Good huntin' and shootin',
Bwanawannabe, Daktari Ron

Woops,

RAB really is serious about the BSI.

this actually counts momentum twice, not just once due to form factor for SD.

you all need to read some real science here, not BS-I!

I think you folks are confusing penetration with knock down power.

When you digest MacPhersons land mark book, Bullet Penetration, we'll talk again.

In the mean time, dont stake your life on the BS-I, or a 600 nitro!

Andy

Can there ever be a substitute for real experience in the field?

There are some well accepted calibre norms for hunting each species. There's probably no need to check a 30-06 out on any scale if you're using it on deer. If you are light compared to these norms you have to take care whatever an index tells you.

From talking to lots of people in the know, I have formed an opinion that I can use my 6.5x55 on moose but with great care over bullet selection, range and placement. It wasn't easy, I had to judge real experience vs prejudice and hearsay and also factor in my own skill and prejudice.

I don't see how any index can have told me that and therefore I don't like them. Not least because I come to an index with prejudice eg 'my 7x57 is as good as any magnum 7mm' and look for the index to prove it. If it doesn't I am tempted to discount it in a way I cannot if someone tells me 'use that and you stand a high chance of losing your game/life.'

Also what is good enough?

Andy,
I think BSI is a useful guage of whomp. I think you are taking it too seriously. It does not claim to tell all.

BTW, I do not understand how you could possibly say that BSI counts momentum twice, since there is only one velocity term and it is first order. Also, the units of sectional density have no reality other than as a ratio between bullets of various weights for a given caliber, by its definition, and that is fact.

Will this BS never end? It is going nowhere.

------------------
Good huntin' and shootin',
Bwanawannabe, Daktari Ron

I prefer to determine the terminal performance of any rifle by first determining the performance of the guy behind the trigger. Except for bullet performance, all other consideration are of secondary importance.....

AD

RAB,

My appologies if I offended you. I certainly did not mean to be rude. Ive always enjoyed your posts.

Re. the .458, I dug through my old reloading notes from winter 1981. Found them tucked away in an old hornady reloading manual that I had used to reload the 458 win and weatherby.

I was getting 2,030 fps with remington factory ammo in a 26 inch barrel Ruger #1. Weatherby factory ammo was 2,600 fps give or take a few fps. My RL-7 reloads using 500 gr WW bullets (yellow box with red WW letters) was a mind numbing 2,160 fps. And this was in the winter. Same load in summer would probably blow out primer. 4320 was 100 fps slower.

It appears that I only shot three bison with the two rifles. (One factory .458, one reload and one factory 460).

My personal experience with heart and spine shots on bison is that the heavier the bullet, the lower the velocity and less effective the caliber is on game.

.338 minimum for one shot kill.

I have always used nosler partitions for practice and load development and have always used premium bullets or better for hunting.

Hatchers original formula used energy x frontal area and that is still a good rule of thumb, scaling from pistol to 120 mm APDS-FS anti-tank guns.

He changed to momentum due to falsified data from slaughter house. (Like any young LT who wants to further his career he told his boss what he wanted to hear).

Take home lesson is I have been very dissapointed with slow large bores like 458.

PS. How did you slect your Botswanna hunt?

Andy

[This message has been edited by Andy (edited 05-10-2001).]

Andy,
What pushed me over the edge, besides this website, was meeting with and talking to John Wilson in Cordova Alaska. He is a world hunter who specializes in the sheep slams, and does everything else too. Africa is a lesser interest of his, but he has been there at least 5 times with rifle and bow. He recommended Ron Young of Expeditions by Ron, having been thoroughly satisfied with his service on many occasions around the world. I called them up and just took the plunge on a plains game special with buffalo added on at a fair rate, in the Okavango. There is never a good time to do it. It just must be done. Something I have dreamed about since I was 10 years old. I too aspire to be a professional small boy.

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Good huntin' and shootin',
Bwanawannabe, Daktari Ron

Andy,

I think frontal area times energy has some truth in it. However with lead core bullets that expand appropriately, I think performance gets better as velocity increases but it I think it falls off as velocity gets past maybe 2600 or 2800 f/s.

I guess I have shot as many phone books, tins of water and trees as most people. However my game shooting is limited to animals no larger than pigs, goats or kangaroos.

But perhaps small calibers like 218 Bee etc on kangaroos 9up to about 200 pounds) may have some relationship to much larger calibers on much bigger game.

So having said that and for whatever it is worth this has been mu obervation on having shot several thousand kangaroos and a lot of pigs.

a 22 magnum is dramatically more effective than the standard rimfire.

A 218 Bee is dramatically more effective than a 22 magnum.

BUT, a 222 is not as good as 218 Bee.

Also, anyone in Australia who has done lots of shooting over the years will also tell you that the old 303/270 was more effective than the 270 Winchester. Same for 303/25 and 243.

I have also shot a huge number with the 270, 308 and 300 Winchester and side by side.

The 308 was the most effective.

My other obseration has been that if energy is similar and bullet expoansion is appropriate, then the larger caliber bullet with more momentum is much more effective.

For example, the 458 with 400 grain Speer bullets at 2000 to 2100, is dramatically more effective than a 300 Winchester. However that may not be momentum related but rther your frontal area X energy as that would make the 458 with 400 grainers over twice effective as the 300 Winchester.

Form an overall point of view of killing effectiveness and trajectory, about 3100 f/s seems to be the number but obviously recoil would be a major issue with big bullets at this speed.

Mike

Mike,

I think we go to the same church.

Aussies shoot the 130 gr in .308 alot more than we do over here, and I think that may be part of your success with .308.

I found 117-120 gr 25-06 more effective than .308 on ferral dogs. So I still am inclined to velocity. this penetrated 16 inches on cattle killing dogs. Always got an exit. the 130 gr .308 only went 12 inches. More momentum, less penetration, and slightly less effective.

The 400 gr flat nose and 350 gr RN in 458 expand rapidly since they are designed for 45-70 and have only 16/1000 thick jacket and large exposed lead on wide mouthed meplat.

Since I was shooting Biterroots, velocity was never a problem and I could go as high as 3,400 fps with no problems even on shoulder or head. 95% or more retained weight and up to an inch diameter expansion. Nothing can survive a hit with a .338, .358, or 375 Bitterroot.

the lighter bullets (like 250 gr 375, 225 gr 358, or 200 gr .338) were more effective than slower heavier bullets.

Put down bison like ground squirrels.

Splat!

Andy

Andy,

Austraina Defence Industries made copies of the 130 Speer and loaded them in 308s for goat and pig culling. I have used this bullet inthe 308, 30/06 and 300 Winchester side by sid and the 308 was the clear winner. Although I often wondered whether twist had any effect because the 308s were always Sakos with 1 in 12 twists.

I have used the 100 Speer in the 270 a real lot.

Your comments on the 308 and 25/06 are interesting and raise another point.

I suspect velocity along the penetration has some influence.

I have always been amazed at how effective the 300 Round Nose Hornady from the 375 is on game like roos. My guess is that it is very blunt to start with and even small expansion will increas diamter and it maintains high speed through the animal.

By the way the mosty devastating shots on big roos that I have seen have come from gut shots with the 300 Hornady in the 375 and the 500 Hornady in the 460, especially with the 1970s version of the bullets.

However if roos were rounded up in a paddock during a hot day until knocked up and were covered in sweat, the damage was nowhere near as much as when they were shot while standing under a tree.

I don't know if it applies to other animals but roos hit way out past 500 yards never go anywhere irrespective of what you hit them with. Could be that they are relaxed or don't know where the shot came from. I have seen heaps of them shot at those distances with 303 military ammo and they just fall over or fall down and get up and fall down again. The same bullet in the spotlight is a waste of time.

I can remember reading many years ago about how deadly the Bitteroot bullets were.

Mike

I have been in agreement with RA from the beginning, but when he explained the BSI from the standpoint of a West Point Grad, I would think even the most ig of gun nuts could understand the theory that "fatter bullets punch bigger holes"....Took me 10 minutes to get off the floor, laughing my a$$ off!!!!! and truer words have not been spoken. The big dog gets the bone boys, thats all there is to it.

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Ray Atkinson

ray@atkinsonhunting.com
atkinsonhunting.com

Thanks, Ray,
You seem to have an excellent understanding of what it is all about.
The BSI is an accounting method, not science.
Oh yeah, I am a West Point dropout, not grad, thank goodness!

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Good huntin' and shootin',
Bwanawannabe, Daktari Ron

Mike,

Are kangaroos monogastric?

that is, do they have one stomach. Posterior fermentors like rock chucks and horses?

A full rumen (ruminant with 3-4 stomachs) would explain the splat of a full tummy when hit with the 300 gr RN.

I just shot about 40 rock chuks with a .223 using 69 gr Federal match ammo (using Sierra 69 gr open point boat tail) and they were very dissapointing compared to a SP.

Andy