Alf,

Then the US military's switch to 62gr and on going switch to even heavier 5.56 bullets, for increased terminal performance, really means, if nothing else, that the bullet will tunmble even quicker, and so enhance terminal effect in flesh, right?

Especially with the M855 62gr bullet with steel penetrator in front, vs. the 55gr M193, right?

(And back to the elephant topic, the 470NE's bullet shape simply makes the distance from PP to CG greater than a similar hemispherical RN. I wonder what the differences in length is between .458" 500gr RN length and the 500gr 470 bullets, or a 450gr .458" RM. I have all three and will compare tomorrow - as well as finally take photos of my recovered bullets.)

JPK

Alf,

quote:

NO I certainly do not buy your latest excuse regarding what you wrote about sectional density, not when for years right here on AR you actually defended your position on Sectional density. Your reasoning is flawed !

Which part of my article is flawed? Where do I mention one fact that is not 100% true?

quote:

Munk's formula ! ( After M.M Munk The aerdodynamic forces on airship hulls 1924)

Airships are always subsonic. Bullets are mostly supersonic. Some rules can be applied and some cannot. But that is just aside, surely we are talking about terminal ballistics and not external ballistics?

quote:

Your piece written is basically proof of this commonly made mistake.

That is precisely why I wrote the article the way it is. The common mistake that is made is that a reloader is told/taught that higher SD increases penetration. This is not true.

quote:

Originally posted by RIP:
I see ALF has got his supercilliousness in a wad again.

Never a Blaser Shooter,
Rip
Riflecrank Internationale Permanente, DRSS, SSSS, BASS, LASS, SLSS
******************************************************
Self Appointed Poobah of C.R.I.P.

Alf's a genius... and must responses be superciliousness????

Bob

www.bigbores.ca

quote:

Originally posted by JPK:
Alf,

Then the US military's switch to 62gr and on going switch to even heavier 5.56 bullets, for increased terminal performance, really means, if nothing else, that the bullet will tunmble even quicker, and so enhance terminal effect in flesh, right?

Especially with the M855 62gr bullet with steel penetrator in front, vs. the 55gr M193, right?

(And back to the elephant topic, the 470NE's bullet shape simply makes the distance from PP to CG greater than a similar hemispherical RN. I wonder what the differences in length is between .458" 500gr RN length and the 500gr 470 bullets, or a 450gr .458" RM. I have all three and will compare tomorrow - as well as finally take photos of my recovered bullets.)

JPK

The original Kynoch solid for the 470 was a gilding metal jacketed RN design with a sharper point then that seen on other Kynoch Nitro Express calibers. John Taylor was one of the first to theorize that the more pointed 470 bullet did not penetrate as much as the more blunt solids for the other calibers. But, he wasn't too sure of that.

Woodleigh changed the front shape of their solids some time in the mid-80s. Previous to that it was more blunt. The new shape was a little more rounded. Not sure why they did that. I don't think that the new shape materially contributes to less penetration. At least, I haven't noticed it on elephants. I have both types and can show a picture of the change if any one is interested.

465H&H

.458 Only,

Thanks for the spelling correction.
But I did think of "getting one's superciliousness in a wad" all by myself.

That attitude is closely related to bitterly clinging to Round Nose solids.

Begs for a superciliousness adjustment.



Never a Blaser Shooter,
Rip
Riflecrank Internationale Permanente, DRSS, SSSS, BASS, LASS, SLSS
******************************************************
Self Appointed Poobah of C.R.I.P.[/QUOTE]

RIP:

What on earth makes you think that I am clinging on to RN bullets ?

Not at all ! I cannot remember when last I actually shot a RN solid from any of my big bores.

I absolutely endorse the use of FN's but what I cannot endorse is the false science that is put forth as to how they do what they do. Especially when there is ample evidence in the world of medical and forensic science to prove this.

You cannot ask me to forgo what is now deemed as basic science in ballistics trauma and it's not like its anything new, its old news.

Alf,

quote:

Which part of my article is flawed? Where do I mention one fact that is not 100% true?

quote:

The common mistake that is made is that a reloader is told/taught that higher SD increases penetration. This is not true.

A question and a statement. I doubt that any answers will be forthcoming, judging by previous situations of similar nature.

Alf, you seem to disagree but cannot say why.

Gerard:
I will oblige!

Everything about that article is wrong! But as you now point out it was done, how do you put it? " tongue in cheek "

As to the second statement:

I care not what reloaders are taught or are perceived to think !

Sectional density as properly defined is proportional to penetration. It is a derivative of a fundamental physical law. You cannot escape it no matter how you spin it! It is a fundamental derivative that defines every aspect of our ballistics system, internal, intermediate and terminal !

Alf,

quote:

Everything about that article is wrong!

Name one, is what I meant. If you point out one instance, we can debate that. Generalities we cannot.

quote:

I care not what reloaders are taught or are perceived to think !

I have to because reloaders use GSC product and the average reloader is not a physics professor.

quote:

Sectional density as properly defined

Have you ever seen a sectional density number given by a manufacturer that was properly calculated? They all use diameter squared. The reloader does not care about the formula, they only care about the final number.

quote:

(SD)is proportional to penetration.

No, it is not. Read my article and you will see that it is not. Here is the link. Also, you could explain this.

quote:

It is a derivative of a fundamental physical law. You cannot escape it no matter how you spin it! It is a fundamental derivative that defines every aspect of our ballistics system, internal, intermediate and terminal !

I agree with you but, once again, the average reloader does not care about it. He is told the lie of higher SD = better penetration and that is what I have been saying all along. It is a lie.

No Gerard ! why should we and I include myself ( i am no physics professor) be subjected to half truths and bogus science ?

You make a big deal about the long range capabilities of your bullets, go so far as to quote from the late Bob Mcccoy's very physics heavy book.

I put it to you that if you accept what you quote from Mccoy why do deny that sectional density is proportional to penetration depth ?

if you accept that BC is a derivative that is representative of a projectiles ability to overcome resistance to penetration then you de facto accept that Sectional density is proportional to that ability to overcome drag i.e. penetrate. Why deny it? your article makes no sense at all.

as to your application of SD you still don't get it ? it's not the proper calculation that's at issue, it's the application of its value in the dynamic process of penetration.

In physics we can state that the projectiles ability to overcome drag is proportional to the ratio of the projectiles mass and the product of the coefficient of drag and it's representative surface area.

this definition is profound in terms of it's dynamic nature.

your examples given are static numbers and they are meaningless unless they are properly adjusted for in a setting of a continuum.

quote:

I put it to you that if you accept what you quote from Mccoy why do deny that sectional density is proportional to penetration depth ?

Then how do you explain this? Feel free to use McCoy's physics heavy book. The pipe dream of what should be is always tempered by the reality of what will be.

quote:

Originally posted by ALF:
RIP:

What on earth makes you think that I am clinging on to RN bullets ?

Not at all ! I cannot remember when last I actually shot a RN solid from any of my big bores.

I absolutely endorse the use of FN's but what I cannot endorse is the false science that is put forth as to how they do what they do. Especially when there is ample evidence in the world of medical and forensic science to prove this.

You cannot ask me to forgo what is now deemed as basic science in ballistics trauma and it's not like its anything new, its old news.

ALF,

Sorry, did not mean to pin the bitter-clinging-to-RN-solids rap on you.
That was meant for some others here.
Very happy that you are a champion of the FN,
and surely must eschew the use of the RN except in health care delivery systems.

Sure, SD drives everything in ballistics. It is the primary driver of penetration and bullet expansion,
until something else becomes more significant.
SD is surely useless without the proper bullet construction and velocity.
Other factors can become more important, overall, than Sectional Density.
Absolute fact.
That is all Gerard was getting at with his parody interpretation of the concept of SD.
A lot of us got it and had a good chuckle about it.
Calculus is not so amusing to most of us.
Nobody uses it in real life, not even rocket surgeons.
Engineers and handloaders read their gauges and tables and measure the real world.
Thanks to science and calculus for making this possible.
Reading the entrails of the theory by mathematics beyond the basics puts most of us to sleep.
Please carry on. Some of the best sleeping potions around can be found here.
Calling all insomniacs ...

Never a Blaser Shooter,
Rip
Riflecrank Internationale Permanente, DRSS, SSSS, BASS, LASS, SLSS
******************************************************
Self Appointed Poobah of C.R.I.P.

quote:

Originally posted by Gerard:

quote:

I put it to you that if you accept what you quote from Mccoy why do deny that sectional density is proportional to penetration depth ?

Then how do you explain this? Feel free to use McCoy's physics heavy book. The pipe dream of what should be is always tempered by the reality of what will be.

Gerard,

The clip from the 470 Mbogo site is a poor one for discussion.

Same FN solid bullet (no SD variation) at narrow range of velocities (about 1500, 2100 and 2400 fps) in a first order medium of plywood boards.

Of course the faster bullet penetrates deeper there.

And a Round Nose solid of same weight and caliber would have penetrated even deeper than the FN, in tightly stacked plywood boards.
And the RN would not have veered either, like it does in game animals and more reality-oriented test media.


Never a Blaser Shooter,
Rip
Riflecrank Internationale Permanente, DRSS, SSSS, BASS, LASS, SLSS
******************************************************
Self Appointed Poobah of C.R.I.P.

RIP,

I agree with you absolutely. The fact that a RN of the same weight, speed and caliber (therefore the same SD) would penetrate better than a FN in this particular test, is proof to the fact that nose shape better determines penetration than SD.

Alf,
In your opinion, which of these three bullets will penetrate the deepest, given the identical frontal shot on an eland, caribou or moose with a 30-06 at 100m.

150gr Sierra Match King SD = .226
150gr Nosler Partition SD = .226
150gr GS Custom HV SD = .226

Gerard:

The 3 examples you show have in terms of your rather limited view the same Weight, caliber, BC and SD and thus now you claim me wrong because you and I know that your HV likely would penetrate the best, followed by the Nosler and then the Sierra..... right so far ?

And now you deduct construction is everything ? yes !

The same applies to the tests in paper or observation of penetration depth in nominals as end result between a FN and RN of same weight, caliber and material composition.

Wrong!

The SD and BC written on the box or cited in your 3 examples are worthless, other than it being a rather crude guide or approximation of a potential to behave in a certain way when induced to motion. It does not mean they will actually do so in practise.

First of all the 3 bullets from a ballistics view are in fact vastly different.

For one they are in terms of mass not the same thing, they may weigh the same but their mass is different. Mass can also be written as Density x length. Density is very important,

Because of the way these 3 bullets are constructed differently their distribution of mass within form relative to the centre of mass is different. Thus their ballistics Geometry is vastly different.

This brings about a whole slew of differences once in flight and when penetration occurs.

For one their ductile deformation and erosion under force of retardation will vastly differ.

Assuming each impact the target at under the same conditions and the path in the target is equal each will behave in their own particular way based on the effect of force of retardation on the projectile.

The Sierra will likely mushroom and even break up thus showing a vastly different dynamic sectional density profile than the other 3. The NP usually mushrooms and loses mass and yours from my own experience will lose its frontal area due to fragmentation and leave a substantial relative high density core behind to penetrate.

The dynamic process still includes SD i.e. mass and representative frontal area in direction of motion for each part of each missile involved.

If you were to explain how each is going to do damage to the target you still have to revert back to the concept of the ratio of mass to orthographic surface area albeit not in point mass mathematical model but from a different way Perhaps from a Eularian model or idealize everything to a fluid mechanical model.

Either way you are stuck with mass and orthographic surface area in direction of motion.

This is fundamental to penetration mechanics no matter how you construct your bullets.

Construction is simply a willful manipulation of distribution of mass and orthographic frontal area.

Alf,

quote:

And now you deduct construction is everything ? yes !

No, construction is not everything. Why did I ask the question about speed then? The moment one hangs a hat on a single factor (SD comes to mind) one is on thin ice.

quote:

The SD and BC written on the box or cited in your 3 examples are worthless, other than it being a rather crude guide or approximation of a potential to behave in a certain way when induced to motion. It does not mean they will actually do so in practise.

That is exactly what I have been saying all along. One of the other factors that determine penetration is motion. SD on its own is worthless without motion and theory and practise do not always agree. I am so glad that we see this in the same light.

quote:

First of all the 3 bullets from a ballistics view are in fact vastly different......high density core behind to penetrate.

In other words, the difference in penetration is due to the fact that the three bullets are constructed in different ways. That is also what I said, we agree on that as well.

quote:

The dynamic process still includes SD i.e. mass and representative.......a willful manipulation of distribution of mass and orthographic frontal area.

In other words, The elements of SD are used, together with many other variables in calculations of internal, external and terminal ballistics. On it's own it means nothing. That is also what I said. We seem to be in complete agreement so, why does it appear that you are arguing the matter?

quote:

Originally posted by 465H&H:

quote:

Originally posted by JPK:
Alf,

Then the US military's switch to 62gr and on going switch to even heavier 5.56 bullets, for increased terminal performance, really means, if nothing else, that the bullet will tunmble even quicker, and so enhance terminal effect in flesh, right?

Especially with the M855 62gr bullet with steel penetrator in front, vs. the 55gr M193, right?

(And back to the elephant topic, the 470NE's bullet shape simply makes the distance from PP to CG greater than a similar hemispherical RN. I wonder what the differences in length is between .458" 500gr RN length and the 500gr 470 bullets, or a 450gr .458" RM. I have all three and will compare tomorrow - as well as finally take photos of my recovered bullets.)

JPK

The original Kynoch solid for the 470 was a gilding metal jacketed RN design with a sharper point then that seen on other Kynoch Nitro Express calibers. John Taylor was one of the first to theorize that the more pointed 470 bullet did not penetrate as much as the more blunt solids for the other calibers. But, he wasn't too sure of that.

Woodleigh changed the front shape of their solids some time in the mid-80s. Previous to that it was more blunt. The new shape was a little more rounded. Not sure why they did that. I don't think that the new shape materially contributes to less penetration. At least, I haven't noticed it on elephants. I have both types and can show a picture of the change if any one is interested.

465H&H

465H&H,

I would love to see the comparison photos. Do you have the old Kynoch (non Woodleigh) profile as well?

I have some 470's too and will include them in the photos I take today.

I believe that if you were to go looking for recent incidence of RN's veering in elephant heads you would find the 470 the leading culprit, both in absolute number and rate of incidence, but this is just my impression from reading various reports here and a few elsewhere. (But it could easily be that the 470NE is the most common choice of both experienced and inexperienced elephant hunters that choose a DR and who don't/won't attribute their misses to their own poor shooting, and who aren't curious enough to go digging.)

JPK

Here is a picture of some unfired and fired Woodleigh RN solids. All of the fired ones were recovered from or after elephant head shots. I don't have a sample of the early Kynoch .470 ammo.




From left to right.

Unfired 550 grain .458, the same recovered, Unfired 480 grain .468 old style solid, next two the same recovered. New style 480 grain .468 solid. New style 500 grain .474 solid, next two the same recovered.

The change in nose shape was small but noticeable. Apparently, Woodleigh did not change the nose shape of the 550 grain .458.

465H&H

Thanks, I will take some photos shortly.

I notice that three of your "old style" .458" 480gr Woodleighs don't have cannelure. I haven't seen that before. Are they the .458" 480gr for the 458wm?

JPK

For the adeherents to the theory that FN's outpenetrate RN's based on nose shape I would ask but a simple question:

Why do you not use FN's for long range shooting ?

Why does NASA build their rockets with conical nose shapes and lastly why in nature do dolphins and game fish not have flat noses. Why do we still see submarines built with conical nose shapes ?

quote:

Originally posted by JPK:
Thanks, I will take some photos shortly.

I notice that three of your "old style" .458" 480gr Woodleighs don't have cannelure. I haven't seen that before. Are they the .458" 480gr for the 458wm?

JPK

JPK,

The two on the left are .458 550 grain, the middle four are .468 480 grain and the three on the far right are .470 500 grain.

It also is now apparent to me after looking closer at the above picture that the fired new style bullets have attained the same shape as the older run of bullets.

465H&H

Alf,

quote:

For the adeherents to the theory that FN's outpenetrate RN's based on nose shape I would ask but a simple question:

Why do you not use FN's for long range shooting ?

Why does NASA build their rockets with conical nose shapes and lastly why in nature do dolphins and game fish not have flat noses. Why do we still see submarines built with conical nose shapes ?

Because they want to slip through their respective mediums with as little disruption as possible. They are not spin stabilised and some of them are subsonic and have their CG forward of the physical center. When supersonic flight is done, the nose shapes are not simple cones or arcs.

quote:

Originally posted by 465H&H:

quote:

Originally posted by JPK:
Thanks, I will take some photos shortly.

I notice that three of your "old style" .458" 480gr Woodleighs don't have cannelure. I haven't seen that before. Are they the .458" 480gr for the 458wm?

JPK

JPK,

The two on the left are .458 550 grain, the middle four are .468 480 grain and the three on the far right are .470 500 grain.

It also is now apparent to me after looking closer at the above picture that the fired new style bullets have attained the same shape as the older run of bullets.

465H&H

Sorry, read .458" where you typed .468". I have noticed that both the hemispherical and the more ellipsoid noses will flatten some.

I have taken photos. What is disturbing is that my great collection of perfectly performing - as in traveling straight through the elephant's brain - but bent, flattened and split Woodleigh bullets is missing. I only have the pretty ones left, but they did the job too.

JPK

Gerard,


The reasoning that you give for discounting sd also applies to any of the other variables you mention.

The only way that you can measure the affect of any single factor on penetration is to standardize all the other factors. For instance, if you want to measure the affect of changing velocity on penetration you must use the same caliber, bullet weight, construction, nose shape etc. If you want to measure the affect of changing sd then you need to only change bullet weight. Although, there are some multivariate statistical tests that can measure the affects of multiple variables. But, that is a much more complicated test and really not necessary.

465H&H

Finally dug up my dug up bullets, and a few others and took photos with my trusty i phone. My cameras have gone missing, my daughter, who is looking at colleges with my wife, must have barrowed them.



From top right:
1. Unfired 500gr .458" Woodleigh solid with the cannelure for the 458wm.
2. Recovered from elephant, 500gr .458" Woodleigh solid. Looks straight but has a slight bend discernible rolling it on a table top. Penetrated straight.
3. Another recovered from an elephant, it also appears straight but has a very slight bend discernible rolling it on a table top. Penetrated straight.

Middle row from right:
1. Recovered from elephant, first generation North Fork 450gr .458" FN solid, nose deformed and bent, shank bent, appeared to travel straight.
2. Unfired second generation NF FN 450gr .458" solid
3. Greatly deformed and bent NF 2nd Gen solid, hit top of tusk socket on the side toward the center of the head, penetrated little and veered sharply.
4. Recovered from elephant slightly bent nose, slightly bent shank, traveled straight.
5. Recovered from elephant slightly riveted nose, slightly bent shank, traveled straight.
6. Recovered from elephant after, iirc, 56" of penetration, divot in nose, began to veer after passing straight through elephant brain with an increasing rate of veer ending about 4-6" off track.

Bottom row from right:
1. 500gr Woodleigh fired from 470NE recovered from elephant head after frontal brain shot, appear that the nose nose slightly flattened, the bullet is straight. I do not recall penetration depth other than that it was more than sufficient.
2. Ditto
3. Ditto
Note: One of the three Woodleighs from the 470NE was used for a killing frontal brain shot, the other two were shot into the dead elephant. My son, when he was seven, got into my recovered bullet collection and mixed up the notes and bullets, so I don't recall which is which and there is no feature of the recovered bullets that distinguishes one from the others. That generally holds true for other bullets except those I recognize from a particular elephant and shot.
4. A bullet recovered from the tusk of an elephant bull I shot. Appears to be a 375 bullet, but there is no way to measure it. I wonder what happened to the fellow who shot it? Grape Jelly?
5. An unfired 500gr FN Gas Check hard cast bullet. At the request of an AR member, I shot several of these, loaded to about 1,550fps, iirc, into a dead elephant's skull. While the bullets chipped and fractured, they all reached passed through the brain.

As I mentioned, I have a great collection of bent, flattened and/or split Woodleighs recovered from elephant heads, but I have not found them since my then 7yr old son got into them. Likewise for more NF FN's and other Woodleighs in better shape. The common denominator of all was that they passed through the elephants brain and traveled straight.

JPK

.458 550gr Woodleigh solid,2125fps penetrated buff head and found in stomach.Straight line penetration.
[URL= ]Woodleigh 550gr fmj [/URL]

quote:

Originally posted by shootaway:
.458 550gr Woodleigh solid,2125fps penetrated buff head and found in stomach.Straight line penetration.
[URL= ]Woodleigh 550gr fmj [/URL]

Bull ... or COW?