A question in another thread prompted this.

We know what makes a solid penetrate deep:

1. Overall drag on the bullet must be minimised as it penetrates. A solid that veers or tumbles creates excessive drag and could break or miss the target within the animal completely.
2. We also know what makes a solid penetrate straight. A complete cylinder shape is good but that will not feed in a typical rifle magazine.
3. We also know that a good solid should retain it's weight. Penetration is the product of momentum and drag. Retained weight is critical.

When it comes to making solids, GSC differs from the notion that a solid should not deform. All solids will deform so, GSC believes that this deforming should be managed so that the deformation enhances the qualities of a solid instead of deforming that harms the qualities.

When a GSC solid strikes, the nose sets back, the meplat becomes larger and the radius between the meplat and the angled nose becomes sharper. The higher the speed at which it strikes, the more these things happen.

1. As the flat meplat grows, it increasingly allows the shaft of the bullet to run in the 'shadow' of the meplat. The drag on the shaft is reduced, the flat meplat has less drag than any other nose shape (round, conical) and, the sharper the radius between meplat and nose becomes, the less drag is generated.

2. Straight penetration, regardless of the angle at which the bullet strikes the target, depends on straight entry of the bullet into the target, shoulder stabilisation and dart stabilisation. To ensure straight transition into the animal, we make very specific recommendations for bullet length/weight and the cartridge in which it is used to keep gyroscopic stability as high as possible. The larger the flat meplat becomes and the sharper the nose radius becomes, the better shoulder stabilisation works. Most of the GSC solids have a boat tail to shift the center of gravity forwards and, together with the nose that sets back, increases dart stabilisation. The bullet remains heavy side forwards.

3. The fact that GSC solids are designed to deform and thereby enhance the qualities of a solid bullet, also prevents it from breaking. Full retention is key to keeping momentum/drag as favourable as possible.

GSC does not care what our solids look like when they are recovered, as long as the recovered shape shows that the bullet deformed and enhanced the requirement for deep and straight penetration. Different? Radical? A purposely deforming solid? Sure, we have heard that for almost 15 years now and only care about getting the job done.

Final shape of bullet means nothing. Is the animal
anchored from the damage the bullet did, yes or no?
That is all that matters.

Gerard, some good pics there and I like the profile which should feed well from a magazine. At what velocities do your solids start to see the nose deformation as shown in the photos - say DG is on average taken within 50 metres perhaps a reference to muzzle velocity.

Most of the photos show extremely even deformation and flattening of the nose on the bullets, what media were they fired into - do the bullets deform in flesh - and what happens when heavy bone is struck at an angle, is the evenly flattened nose shape retained or in fact is the nose shape we see created by hitting bone either straight on or at an angle?

A bullet I am keen to try out in my 404 one day but would be at around 2250fps MV, no ramped up velocities for me.

" As the flat meplat grows, it increasingly allows the shaft of the bullet to run in the 'shadow' of the meplat. The drag on the shaft is reduced, the flat meplat has less drag than any other nose shape (round, conical) and, the sharper the radius between meplat and nose becomes, the less drag is generated. "

This is a fallacious assumption:

The bullet is in a cavity irrespective of its nose shape ! Cavitation is not a function of nose shape ! all shapes cavitate.

If our target is a fluid, cavitation is a function of the mass density of the fluid and its vapour pressure, it has nothing to do with the nose shape. Whether you are firing a ball, a RN or any shape cavitation will occur if a cavitating regime exists.

As the bullet is in the cavity only pressure drag ( form drag) is at issue. Friction drag is at a minimum.
( as long as the minimum velocity for cavitation is upheld)

As the meplat gets bigger pressure drag increases . This is fact. ( unless you are shooting your bullet into a shear thinning liquid)

Pressure drag is directly proportional to the size of the presenting surface area and the square of the velocity of the penetrating body.

To boot energy is lost to the process when plastic deformation of the nose occurs, thus less energy is available to overcome resistance to penetration.

Formation of a cavitation bubble around a fast moving object in a liquid is definitely shape-dependent: super-cavitating underwater projectiles have a nose precisely designed to maximize the effect, with a flat disc.

Even in less-than-ideal medium, the nose shape makes a difference:




These bullets were fired in a laterite dirt bank, one from a .458WM (Hornady round nose), the other from a .458 Lott at 2160 (CEB #13).

It does not show as well on the picture than when you hold the bullets, but whereas the round nose is deeply scored all over, the CEB has bright, almost untouched areas aft of the nosecone.

BTW, penetration was something like 16" vs 27" (from memory, give or take an inch). Granted, the .458 WM is 100 to 150fps slower than the Lott, but still...

D R Hunter,

The user judges the result by the outcome and we ensure that the outcome is more consistent and reliable. At GSC we realise that the route to better reliability lies in how the shape changes. We would much rather have recovered bullets that look like this:



rather than this:



Eagle27,

The nose of the bullet starts setting back visibly from impacts around 1800fps. However, the shape change is not linear to speed but increases disproportionately. Because GSC solids enhance the qualities of linear penetration when they deform, we recommend a speed that is 50 to 100 fps under the maximum pressure for a given cartridge and bullet combination.

The bullets shown in my first post were all recovered from animals. The bullets below were recovered after hitting a variety of bone and other animal material. (The first and fifth from the left are unfired as a comparison.) It does not matter when the deformation of a flat meplat is slightly uneven. It will cause the shaft to start yawing as it rotates, but it does not get far enough out of line to cause the bullet to start curving the path it follows. The requirement here is to have some flattening to enhance the diameter of the meplat and the sharpness of the shoulder, as well as maximise the increase in shoulder stabilisation and dart stabilisation. This only happens reliably with GSC solids, as far as I know.



Alf,

The problem with theory and practise is that theory sometimes does not include all the variables and that practise usually does. When this happens, although the theory is correct, theory does not fit practise.



The practical problem is that the penetrating bullet deals with a very resilient skin (that contains some fluid), bone (that contains a different amount of fluid), the internal organs of the animal (that all contain different amounts of fluid again) and so on. It is a fact that different meplat shapes will cause differing diameters of cavitation, if speed and caliber are the same. All bullets yaw around the direction of penetration and some nose shapes allow more yaw before the shaft gets out of the 'shadow' of the nose shape. When the shaft gets out of the 'shadow' of the cavity formed by the nose shape and the speed at that point, it can contact an object and be steered in a different direction.

Examples are below.



The factors that will promote linear, deep penetration are shoulder stabilisation, dart stabilisation and the largest possible temporary cavity diameter. GSC solids reliably give that, because they deform in a predetermined manner. Below are extreme examples of this in practise.



Alf, you say that energy is used when the bullet deforms plastically and this is true. We have found that this energy is better used in a controlled and pre-designed deformation that promotes linear penetration, rather than an uncontrolled breaking or bending of the bullet that does not.

These solids and softs were recovered from hippo and buffalo in Zim and Australia in 2013. Nothing is better than the Woodleigh solids pictured to the right. The softs are fine for buffalo. And, they look so nice, they belong in a vintage double rifle!
Cal

I agree Woodleighs are great so are Hornady DGS.

There are lots of photographs of jacketed lead solids on the forum. The topic still begs the question: Traditional thinking or is there a better way?









It reminds me of the old saw that goes: "When the going gets tough, the tough get going."

cut the BS man

Phillip A:

If we shoot various bullets into a blocks of gelatine, all form cavities ! without a cavity there is no penetration It is a simply fact of life..... hence they all cavitate !

Now granted blocks of gelatine and human tissue are not fluids, they are solids, albeit soft solids in some instances.

The mode of cavitation in solids are different to the mode of cavitation in fluids.

Living tissue may be water rich but living tissues are not fluids, physically there are all solids!

From a physical perspective they behave like solids , they have structure, do not flow and above all living tissue supports shear...... that is fact so in terms of cavitation their mode of handling stress does not follow the rules of fluid mechanics although in the modelling of projectile penetration fluid mechanical property models are often assigned for expediency.

A simple point to prove this is the fact that if a shoot a bullet into a pool of water it penetrates and once it has done so there is no cavity left in the water. If the same bullet is fired into a living body there is a tract left behind.... short and simple.

Cavitation in fluids, and i am going to repeat this slowly, is a function of the mass density of the fluid and it's vapour pressure. This is simple physics. No where in the mathematical cavitation regime is nose shape accounted for.

A cavity will ensue if flow conditions for cavitation exist around the projectile. ie If boundary conditions exists in the flow field around the body where the fluid pressure drops down to the vapour pressure of that fluid a cavity will ensue.

This is not nose shape dependent. Bernoulli says so ! Go look it up

Round balls , chunky projectiles, oblong projectiles of all shape, all will grow cavities at some point on their profile as long as the fluid pressure drops down to the vapour pressure of that fluid because of flow around the body.

Where shape comes to play is at what point on the geometrical shape the cavity will form. The FN creates a condition where the separation point is on the edge of the meplat thus most of the shank of the projectile is in the cavity. Thus a "super cavity" is formed.

As opposed to say a round ball where the separation point is on the equator of the ball.

And this is not theory this is every day reality. Anyone who has plumbing in their home or has blood in their veins have to deal with this problem. The living human ( animal) body is uniquely adapted to counter cavitation in our blood vessels.

Stability of the projectile is not dependent on whether there is cavitation or not, but simply a function of mass distribution within geometrical shape and the location and direction of unbalanced forces on that body.

Alf,

Having said all that, what it comes down to is that you say that certain shapes will form cavitation at different speeds. The speed and shape determines how big the cavity will be?

Is your last sentence not scientific speak for: Dart stabilisation is good and shoulder stabilisation is good? (Alf: Stability of the projectile is not dependent on whether there is cavitation or not, but simply a function of mass distribution within geometrical shape and the location and direction of unbalanced forces on that body.)

Shootaway,

Are you saying that the pictures are BS?

Let me state this without reserve.

I am a proponent of FN solids , I am a proponent and long time user of Gerrard's bullets , I fully endorse his products.

For the first time we now have limited access to CEB bullets, I have ordered some and will be using them. I believe they are on to something that is useful.

What I am not a proponent of is fallacy regarding how they work and more specifically the fallacies regarding the mechanics of wound ballistics.

Gerard: Again no! it is all about mass distribution in form and the location and direction of unbalanced forces acting on the body ( mass) in motion. whether tail drag , dart or shoulder stabilization it is all about mass distribution and manipulation of the point of pressure location on that mass.

quote:

Originally posted by shootaway:
cut the BS man

you cut the bs.

Alf,

I hear you but I think it is necessary to say things so that it can be understood by a wider group of people. Most people understand what dart stabilisation and shoulder stabilisation are. Given that external ballistics (the bullet in flight) changes completely when we talk terminal ballistics (the bullet in flesh and bone) we need to explain why one shape is preferable over another.

The shape and construction required to efficiently penetrate armoured steel differs from the shape required to efficiently penetrate water. Whether the impact is supersonic or subsonic also plays a role when we consider construction and shape. The shape and construction of the bullet to give the best terminal result in building material (sand, wood and cement) differs from that which gives the best result in tissue.

Linear deep penetration in tissue is easy. Linear deep penetration that causes maximum trauma in tissue is more complicated.

We then have to answer the question: What qualities do we look for when we want maximum, reliable, consistent performance in a solid bullet?

Of course any animal can be killed with any bullet. Elephant have been killed with a 22 short rimfire and duiker have been shot with a 50BMG. We have to ask (and answer), what will make one solid bullet better than another.

Alf,


1) Cavitation in physics, the formation of vapour bubbles in a liquid

2) Cavitation (biology), the formation of cavities in an organ

3) Cavitation (elastomers), the unstable expansion of a microscopic void in a solid elastomer under the action of tensile hydrostatic stresses


The "cavitation" referred to when an object moves through a fluid at elevated velocities is 1). Of course any projectile moving through an animal's body will leave a biological cavity, but the theory on how a bullet can ride in a cavitation bubble is based on physics. And there, the shape is relevant.

The first research into this was based on supercavitation applied to naval torpedoes, and a parallel was drawn with a bullet moving through soft tissues.

The first "superpenetrator" bullets were actually built with a flat disc on the nose.

Phiilip A.

Norbert Hansens orginal writings on how his bullets worked were depeleted from Wikipedia because from a physics point of view the arguements were fatally flawed. The principal was sound but the mechanics was flawed. People made erroneous deductions based on flawed mechanical arguements.

Many people including authors of books and articles books copied his theory verbatim and that does not make it right.

They assigned mechanaical behaviours to cavitation or the fact that the projectile rides in a cavity, that is factualy wrong.

A round ball as example does not supercavitate and yet it is stable !

or

Ice is water . It is a water rich environment in fact it is pure water but ice behaves like a solid..... it is the solid phase of matter. thus mechanically it adheres to our understanding of solid mechanics.

Bone contains about 80% water and yet bone behaves like a solid. It supports shear and thus exhibts stress and strain behaviour.

It is very important to define the structural mechanical behaviour of the target when discussion of penetration mechanics. Without defining the constituative reaction of the target to stress we can not proceed with any discussion on how penetration works.

Gerard,

First, I suggest you just ignore Shitaway. He has nothing to contribute and his attempts to detract fall universally on ears made deaf by the combination of his belligerence and his idiocy.

To the topic, all of those "failed" Woodleighs resemble your bullets when each encounters similar material in target. Wish I could cut and paste photos efficiently...

As you know, I am an early user and proponent of FN solids similar to yours. In fact, if they had been available when I selected my FN solids I would have selected yours. I agree that mild riveting is no barrier to performance, but I have also found that divoting, when one side of the bullet is deformed more markedly than the other, leads to curved penetration.

Moreover, I have found that bullets similar to yours deform more readily in elephant heads than Woodleighs - until the Woodleighs have lost a great proportion of their velocity, at which time they have substantial tendency to tumble. When they tumble they are prone to deformation, especially when bone is encountered. I have never had a Woodleigh travel in anything but a straight line, even after beginning to tumble (and penetration is very limited after tumbling begins in any event, limited to 9" or so.)

The Woodleigh's tendency to tumble after having lost much of their velocity is a detriment when maximum penetration is required. That is the case on all body shots but that is NOT the case with brain shots on elephants. Limited penetration is a benefit on elephant brain shots, so long as penetration is adequate.

Unless stopped by the off side zygomatic arch on a side brain shot, or exiting on a side brain shot, all Woodleighs I have shot into elephant head have penetrated about 36", including those stopped by the spine after traversing the skull front to back. 36" of penetration is adequate and some. Penetration with a FN is harder to determine because so many exit or penetrate so far they are lost, but it is double or more, unless stopped by substantial bone.

In know you disagree, but the substantially greater effect on an elephant given a missed brain shot with a Woodleigh vs. a FN are plainly obvious. Those substantially greater effects buy the hunter time to deliver a proper brain shot or a killing body shot (with a FN solid) despite having missed the initial brain shot.

I know you also disagree with my contention that the more rapid transfer of energy by a Woodleigh RN is the cause of the plainly obvious greater effect when a brain shot is missed. But 5,100lbs' of energy transfer over 36", within roughly 18" of the brain constitutes a substantially more concentrated blow to the elephants brain that the same energy applied over 72" inches with much of the energy transferred several feet from the skull and brain.

When it comes to buffalo, for a first shot, 36" of penetration is plenty adequate, but on subsequent shots more isbetter, just like with elephants.

So, the ideal prescription is to load a Woodleigh RN for the first shot and then GSC's or similar for the second and subsequent shots!

As an aside, and to all of those arm chair elephant hunters who might criticize my prescription as "planning to fail" to make a proper brain shot, I will relate the results of my poll of PH's regarding their clients' success on frontal and side brain shot - substantially below 50%. And on their own brain shots - better than that but far from perfect (it was difficult to pin them down, they were typically enthusiastic in reporting anonymous client shortcomings but reluctant in reported their own - go figure.) My own success rate is about 75%, but that includes several elephants that might have been knocked unconscious or killed outright by a near miss rather than perfectly brained since their eye had some reaction to touching - and I also believe an elephant shot in the lower brain is both much more apt to drop into the sphinx position and to retain some residual eye reaction.

JPK

Hello all. As a matter of interest, the picture of the broken brass solid looks like the one ganyana first posted of a pmp 375, as an example of all solids failing now and then . As i am a fan of the pmp solid in 375 i followed up at the time and eventually traced and spoke to the zim PH who had given a broken 375 brass solid to ganyana. This bullet was found in the chest of a bull ele after penetrating the skull and neck from a frontal shot How it got there quite puzzling and how it got there in 2 pieces even more puzzling.

Gerard your solids have a boat tail. Are they stable at kill or be killed distances ie 10 feet

JPK,

quote:

To the topic, all of those "failed" Woodleighs resemble your bullets when each encounters similar material in target.

I really do not see how you get there. The only deformation GSC solids show is the shortening and expansion of the nose. In extreme cases where a jacketed lead bullet fails completely, breaking into several pieces and winds up with no repeatable shape whatsoever, a GSC solid still retains all the qualities that allow a solid to enhance penetration.

quote:

I am an early user and proponent of FN solids similar to yours.

quote:

I have found that bullets similar to yours

quote:

the substantially greater effect on an elephant given a missed brain shot with a Woodleigh vs. a FN are plainly obvious.

Here is the difficulty. Hunters have used a variety of flat nose bullets and find that the various makes work in similar manner. The assumption is therefore that GSC FNs will also work in a similar manner to the other flat nose solids that were used. The bottom line is that they do not.

Any comparison that is made with any other bullet cannot be valid. Would you compare a 168gr 30 caliber Match King to a 165gr 30 caliber Game King? Both have hollow points, boat tails and unbonded lead cores with copper jackets. The terminal performance would be remarkably different and those differences are the result of deliberate design changes.

It is difficult to believe that there are several problems that have been solved by GSC but this is the convention we have been up against almost since inception. Until you have used GSC (not similar or looks like GSC) no comparison can hold water. I have been in the gun business since 1979 and I know what is in the market and how it works. I am very happy with the place that GSC occupies technologically, compared to everything else that is out there.

Phil,

From my very first post: " Most of the GSC solids have a boat tail to shift the center of gravity forwards and, together with the nose that sets back, increases dart stabilisation. The bullet remains heavy side forwards."

From our technical profiles ( I am busy working to get the FNs done, ask if the bullet in which you are interested does not appear ) we recommend a gyroscopic stability factor of at least 2. That is consistently the highest in the industry and there is no need to consider a bullet that has to "go to sleep" as it were. The boat tail on FN bullets play no role in the stability of the bullet.

Gerard,

Look at your deeply riveted, really expanded bullets vs. the riveted steel jacketed RN's.

Look at your banana shaped bullets vs. the bent steel jacketed RN's.

I have fish tailed recovered NF's and flattened NF's as well, I am sure you have recovered examples of your bullets will similar deformation.

Neither the NF's or your split their cases, since they don't have a case, which is pretty much the only difference as I see it.

I hear you on the "not similar" issue, but - and perhaps I am mistaken - I have been under the impression that GSC and NF flat nose solids of the older design, under Mike's ownership, are quite similar. Am I so wrong?

Even if they are dissimilar my post remains relevant because of the greater energy transfer over a shorter time and distance span than a Woodleigh or similar RN delivers compared to any deep penetrating FN, as well as the correspondingly and obviously greater effect the Woodleigh RN's have when the brain shot is imperfect. ~5,100lbs' over ~36" and all within ~18" of the brain compared to the same energy transferred over more than twice the distance with a substantial proportion of the transfer occurring a yard and more from the brain.

I hope to resume elephant hunting in the not too distant future, though I have a stock of the older NF's, since I can now easily get your bullets here I will have to give them a try - but for second and subsequent shots!

JPK

My only experience with Woodleigh solids has been with DR's. I've seen no significant bullet deformation, but haven't been impressed with their penetration either.

I've used GS solids in 458, 416, and 375. They penetrate beautifully and chop a nice hole, sort of like a wadcutter. My only complaint about GS solids is that it is hard to recover them.

JPK,

quote:

Look at your deeply riveted, really expanded bullets vs. the riveted steel jacketed RN's.

I see where the misconception is. Let us put speeds to the photographs. The really expanded GSC bullets shown in picture 2 and 5 in my first post and the first and last pictures in my second post are very similar in appearance. These bullets were going at 2500fps to 3000fps. Despite this speed all the bullets show sharp edged, relatively flat meplats and no tumbling or weight loss.

None of the badly broken jacketed lead bullets were going faster than 2300fps. These bullets either came apart completely, some tumbled and had flattened bases. Despite going 200fps to 700fps faster, GSC solids remained reliable and did what they are designed to do.

quote:

Look at your banana shaped bullets vs. the bent steel jacketed RN's.

Again, none of the GSC "banana shaped" solids lost their integrity to carry on doing what solids are supposed to do. The GSC solids remained meplat forwards and got the job done. The jacketed lead bullets show evidence of tumbling and random structural failure at 500fps less.

quote:

I have fish tailed recovered NF's and flattened NF's as well, I am sure you have recovered examples of your bullets will similar deformation.

I have never seen a flattened or fish tailed GSC solid or a photograph of such a bullet. If anyone has a photograph, please post it so that we can see it.

quote:

Neither the NF's or your split their cases, since they don't have a case, which is pretty much the only difference as I see it.

If you cannot see that the GSC solids did not shed weight, did not tumble, that the meplats became more sharp edged and that the jacketed round nose bullets did not do this, there is no point in showing these photographs or describing the qualities. Do the photos #1, 3 and 4 in my first post and photo #3 in my second post really look similar to the jacketed lead bullets in my third post? The speeds were similar.

quote:

I hear you on the "not similar" issue, but - and perhaps I am mistaken - I have been under the impression that GSC and NF flat nose solids of the older design, under Mike's ownership, are quite similar. Am I so wrong?

There is a big difference in the hardness of the materials used and there is a big difference in the lengths and the designs. The two types were not made to react in the same way. Again I have to stress the fact that there is currently no product that works in the same manner as GSC solids or GSC expanding bullets, for that matter.

quote:

Even if they are dissimilar my post remains relevant because of the greater energy transfer over a shorter time and distance span than a Woodleigh or similar RN delivers compared to any deep penetrating FN, as well as the correspondingly and obviously greater effect the Woodleigh RN's have when the brain shot is imperfect. ~5,100lbs' over ~36" and all within ~18" of the brain compared to the same energy transferred over more than twice the distance with a substantial proportion of the transfer occurring a yard and more from the brain.

The post remains relevant as a comment only on the makes mentioned. It is in no way relevant to the way in which GSC solids react and work.

As a matter of interest, we have a report of a PH who had to shoot an old bull elephant in self defense. In this instance the GSC bullet lost weight, veered and did not behave as we want our solids to behave. He was defending a group of people whom he was not really responsible for and he managed to turn the bull three times without shooting. When the elephant came in for the fourth time, he stood his ground and fired a frontal brain shot from about 15 paces. The elephant went down and the bullet was eventually recovered from the neck. After exiting the skull it was caught by the skin, turned and lodged lower down. It had retained 134 grains of weight. He was using his 300 Win Mag and a GSC 160gr HV. That is the only shot that I know of, where a GSC bullet shed weight on an elephant. The fact that it was a hollow point expanding bullet and that it probably impacted at over 3000fps, may have something to do with the loss of weight.

"The boat tail on FN bullets play no role in the stability of the bullet."

Again I respectfully disagree.

The stability of a projectile in dense media is subject to the same considerations that determine stability in flight. (The theory of motion of a bullet around it's centre of gravity in dense media with applications to bullet design Kent RH Aberdeen Proving Ground Maryland 1957)

ie the distribution of mass within form and secondly the presence of unbalanced forces that act on the projectile. As form differs between a FB and BT bullet it is given that mass distribution is different and hence the effect of an external force would be different between the two shapes.

As to the behaviour of cavity riding projectiles in water or dense media.

Projectiles within a induced cavity exhibit very specific motion behaviours. One of these behaviours is the phenomenon of "tail slapping"

From previous posts I have made on this subject:

Tailslapping:

A phenomenon observed in supercavity running projectiles in fluid ( water) where the tail end of the cavity running projectile impacts and even penetrates the wall of the cavity.

The implication of this behaviour is that it induces drag, and based on the shape of the tail end of the projectile may add to stability of the projectile within the cavity or in the case of boat tailed projectiles actually destabilizes the projectile within the cavity

( Source: Janzon B High Energy missile trauma: A Study of the mechanisms of wounding of muscle tissue: Submitted as a Doctoral thesis University of Goteborg Sweden 1983 )

The frequency and duration of tailslap is directly related to the slenderness ratio of the cavity running projectile. ( Zhang et al Harbin Institute of technology Harbin China)

Slenderness ratio defined as the ratio of projectile diameter to length.

The larger the slenderness ratio ie the short “fat: projectile will impact the cavity with greater frequency and will be in contact with the cavity wall longer than a projectile with a small slenderness ratio.

Projectiles in dense fluid targets ( water) are subjected to the same external forces as projectiles in air ( gas) ie Lift, Drag and Overturning moment.

Though the magnitude of the forces are far greater than in air.

May A: Water entry and cavity –running behaviour of missiles: NAVSEA hydoballsitics lab Marryland
1975

I have read with some interest the discussion ( and pissing contest) among AR members) of bullet design for DG. I am sure that GSC bullets or CEB bullets would work fine for me. I stay with Woodleigh 570 solids because they have worked. And I have confidence in them. The bullets shown here were recovered on a buffalo I took in Moz in August. The bullet on the left is a custom from SA 500 Jeffery; the bullet on the right is a Woodleigh 570 solid shot from a 500 NE. A third bullet was not recovered. All three shots were on a running buffalo we jumped, and they all entered the right hip and lodged at the skin of the left shoulder. I don't don't know the diagonal distance-but I do know the Woodleighs work for me.

I agree its a personal confidence thing,which is quite subjective and based on ones own experience. I am sure you shoot/hunt better when you are confident in your bullet and rifle. And when bragging about the penetration capability of your rifle in camp, its also nice to shoot through big mopane or tamboti trees in front of your mates. The pmp round nosed brass solids from my 375 go through the same trees the barnes flat nosed wont---one cant have that!!!!.

phil:

Your observation regarding RN's vs FN's in trees is certainly not unusual.

If we look at optimum nose shape for solid material penetration it is not the FN.

There is ample evidence in the penetrating mechanics literature that support the use of a conical round nose shape over any other shape when penetration of solids such as concrete, metals or soils are on the cards.

The shape that the penetrator nose erodes to during penetration also assumes this shape.

On the ability to penetrate wood:

I don't eat treewood.

There was an interesting testing done by Estergaard (who developed the 470 Mbogo)
http://www.470mbogo.com/BigBores/BigBores.html
He had to use plywood for the tests because wetpaper could not contain the roundnose solids. Here are his own words:
"The newspaper test was a total failure period. Wet paper was tried and dry paper was tried but whether I tried to put 9 shots or 3 shots into the 12 by 12 area we constantly lost bullets. After lining up the barrel for left/right and up/down a shot into the center of the 12 by 12 area exited the box within the first 28 inches. This was a common occurrence and many of the shots would wonder 4 or 5 inches and follow the track of a previous shot. The paper was changed after every three shots and we still had problems gathering information that would relevant. So the paper test is out. Does anyone need a pick-up truck load of paper?"

It reminds me of the joke about the person looking for his coin under a streetlamp. No, he didn't drop it there but that is where he had light for searching. So here, Estergaard used plywood, not because it was anything like animal tissue but because wet newspaper couldn't contain the round nose solids.

Michael in the Terminals thread had to stop round nose solid testing in order to protect his shooting range from wild escaped bullets.

Anyway, if someone wants to shoot trees, yes, the round nose would be great. But for hunting, the flat-nose is surely the choice and Gerard's evidence of actually having the flatnose grow is especially intriguing and desirable.

quote:

Originally posted by 416Tanzan:
On the ability to penetrate wood:

I don't eat treewood.

There was an interesting testing done by Estergaard (who developed the 470 Mbogo)
http://www.470mbogo.com/BigBores/BigBores.html
He had to use plywood for the tests because wetpaper could not contain the roundnose solids. Here are his own words:
"The newspaper test was a total failure period. Wet paper was tried and dry paper was tried but whether I tried to put 9 shots or 3 shots into the 12 by 12 area we constantly lost bullets. After lining up the barrel for left/right and up/down a shot into the center of the 12 by 12 area exited the box within the first 28 inches. This was a common occurrence and many of the shots would wonder 4 or 5 inches and follow the track of a previous shot. The paper was changed after every three shots and we still had problems gathering information that would relevant. So the paper test is out. Does anyone need a pick-up truck load of paper?"

It reminds me of the joke about the person looking for his coin under a streetlamp. No, he didn't drop it there but that is where he had light for searching. So here, Estergaard used plywood, not because it was anything like animal tissue but because wet newspaper couldn't contain the round nose solids.

Michael in the Terminals thread had to stop round nose solid testing in order to protect his shooting range from wild escaped bullets.

Anyway, if someone wants to shoot trees, yes, the round nose would be great. But for hunting, the flat-nose is surely the choice and Gerard's evidence of actually having the flatnose grow is especially intriguing and desirable.

What many miss is that Micheal also proved that an incorrect nose shaped flat point does not penetrate straight and doesn't work well. He also proved that some bullets classified as round nose, yet had a very flat meplat such as the 320 grain 9.3 Woodliegh solid and out penetrated every other bullet tested. People do not seem to focus on the whole thread only a small amount of info.

To me you are trying to complicate a simple fact.
You use a solid for deep penetration...period
A soft point for maximum dissipation of energy
And a controlled expansion bullet for a little of each

Just take the same bullet shoot it at the same velocity out of the same gun at the same media and the solid that goes farther wins, who cares what the bullet looks like.

quote:

Originally posted by raamw:
To me you are trying to complicate a simple fact.
You use a solid for deep penetration...period
A soft point for maximum dissipation of energy
And a controlled expansion bullet for a little of each

Just take the same bullet shoot it at the same velocity out of the same gun at the same media and the solid that goes farther wins, who cares what the bullet looks like.

Micheal's tests did just that.

ja well like I said in my 375 the only solid that did not exit cow elephant skulls from the side brain shot,and the finishing shot through top of skull was the barnes flat nosed. The PMP round nosed always did even on big bulls and even when the zygomatic arch was hit. On frontal shots the pmp solids penetrate out the back of neck if angle is steep and otherwise through the back of skull into the neck. Thats good enough for me.

The flat nosed solid that is now very popular with kruger park rangers(who rave about its straight line penetration) is the dzombo brass solid which has a much smaller meplat than than the barnes ,north fork or CEB. And then there are some south african PH's who swear by Gerards flat nosed solids for elephant.

So its quite a mixed bag...at the end of the day its probably what you are confident with when standing in front of an advancing bull ele!!

On buffalo, every type of solid I have used penetrates deep enough, from the front or rear.

Thats my 2c worth--have a great evening.

Alf,

If one looks at a theory in isolation, a conclusion can be drawn. For instance that a boat tail is less stable than a flat base. This can be proved by comparing the gyroscopic stability (Sg) factor of two otherwise identical bullets where the nose and shaft are concerned, except that one has a boat tail and one has a flat base.

Take our 380gr .416gr FN for instance. At a typical launch speed it has an Sg of 2.04 with a boat tail and 2.14 with a flat base. So a boat tail has worse stability than a flat base. That fact can be proved and, as a single theory it cannot be disputed.

Looking at the bigger picture, where more factors are considered, we see: The Sg increases as the bullet goes downrange so, does it matter whether it arrives at the animal with a Sg of 2.8 or an Sg of 2.9? Anything more than 2 is more than enough to give a stable transition from air to tissue and one only needs a little more than a factor of 1 for stable flight. Is the small decrease in Sg, with a boat tail,not offset by the fact that a boat tail shifts the center of gravity forwards, that a boat tail increases the speed and energy of the bullet when it strikes and it increases the dart stabilisation of the bullet as well. When the bullet strikes at higher speed and with more energy, the nose sets back more, the edge of the meplat becomes sharper, there is less total drag and and and.....

If the boattail versus a flat base will cause the bullet to be unstable in flight, of course we have to pay attention to that. Have a look at some bullets in our SP range. Some have flat bases and there is a good reason for it. However, it is usually a collection of factors that make up the good reason and not a single item in isolation.

quote:

Alf: There is ample evidence in the penetrating mechanics literature that support the use of a conical round nose shape over any other shape when penetration of solids such as concrete, metals or soils are on the cards.

This is true where slow speeds are used and the penetrator is driven with a weak force. Driving a spike with a hammer or using a spade to dig a hole. When things happen at supersonic speeds and the driving force is strong, relative to the penetrator, maximum disruption is caused by a flat face.

raamw,

I hear you. Consider though that the success of a solid is measured not purely by depth of penetration. It must have adequate penetration and also cause as much disruption as possible while tracking straight into the animal. For example, it would be possible to have a solid that is capable of 10 feet of penetration with a permanent cavity that is half an inch in diameter. Another solid is only capable of 8 feet in depth but it gives a permanent cavity that is three quarters of an inch in diameter. The target is a maximum of 6 feet at the widest point. Why use solid #1 instead of solid #2 when #2 will give a better chance of sucess?

Phil,

quote:

And then there are some south african PH's who swear by Gerards flat nosed solids for elephant.

These are the guys who have tried them of course.

That brings us back to the question: Can a solid enhance those qualities that allow a good solid to become better instead of worse or staying the same, as it penetrates? Is it possible and is it desirable?

Correct me if I am wrong, solids are used for maximum penetration,to penetrate body mass, organs blood vessels and break bones. If I use a bullet that goes completely through an animal I stand a greater chance of accomplishing this no matter what the angle, I personally have little interest in a solid that expands a little and does not achieve max penetration, this would be a controlled expansion in my book.

If all bullets tested surpass the required max penetration than #2 on the list would be the cavitation damage
Think of this bullet #1 breaks a front leg runs up along the spine and stops short of the hip/rear legs, no organs hit just muscle damage...that animal is gone

Bullet2 does the same but continues to the rear hip leg area and breaks one or both, he it doing donuts on the ground,and a follow up shot is certain, penetration does matter

You are right, penetration is paramount. In your scenario the shallow penetration bullet will not get the job done and the bullet that breaks the back leg/hip is the better bullet. Sufficient penetration and damage is vital to success.

This comes down to using the right combination of cartridge and bullet for the job at hand. I have often said that any cartridge/component combination incapable of an exit on a broadside shot, cannot be used for a straight going away shot. It will not reach the vitals and, hoping to break the skeleton somewhere in the back of the animal is too risky. This cartridge/component combination is inadequate for the specie that is being hunted.

quote:

Originally posted by Gerard:
You are right, penetration is paramount. In your scenario the shallow penetration bullet will not get the job done and the bullet that breaks the back leg/hip is the better bullet. Sufficient penetration and damage is vital to success.

This comes down to using the right combination of cartridge and bullet for the job at hand. I have often said that any cartridge/component combination incapable of an exit on a broadside shot, cannot be used for a straight going away shot. It will not reach the vitals and, hoping to break the skeleton somewhere in the back of the animal is too risky. This cartridge/component combination is inadequate for the specie that is being hunted.

I completely agree with this analysis.

A hunter may select a good soft point for his first shot at, say, a cape buffalo, but he should select an adequately penetrating solid for his second and subsequent. Easily controlled by how one loads his rifle.

The same for elephants. If you are willing to take a first shot which is a body shot, you ought to be using bullets which offer pass through capability. the same for all subsequent shots.

On the other hand, if your first shot is going to be a brain shot, and only a brain shot, your first shot needs only adequate penetration to traverse the skull, front to back and side to side, plus about 8" or so in the event your frontal is low, so it can break the joint or spine. That opens up the selection of solids.

JPK

quote:

Originally posted by JPK:

quote:

Originally posted by Gerard:
You are right, penetration is paramount. In your scenario the shallow penetration bullet will not get the job done and the bullet that breaks the back leg/hip is the better bullet. Sufficient penetration and damage is vital to success.

This comes down to using the right combination of cartridge and bullet for the job at hand. I have often said that any cartridge/component combination incapable of an exit on a broadside shot, cannot be used for a straight going away shot. It will not reach the vitals and, hoping to break the skeleton somewhere in the back of the animal is too risky. This cartridge/component combination is inadequate for the specie that is being hunted.

I completely agree with this analysis.

A hunter may select a good soft point for his first shot at, say, a cape buffalo, but he should select an adequately penetrating solid for his second and subsequent. Easily controlled by how one loads his rifle.

The same for elephants. If you are willing to take a first shot which is a body shot, you ought to be using bullets which offer pass through capability. the same for all subsequent shots.

On the other hand, if your first shot is going to be a brain shot, and only a brain shot, your first shot needs only adequate penetration to traverse the skull, front to back and side to side, plus about 8" or so in the event your frontal is low, so it can break the joint or spine. That opens up the selection of solids.

JPK

I seldom disagree with JPK but in this case I have to. I know he will understand.

There is no need for a bullet to exit the side of an elephant on a broadside body shot. Elephants are extremely easy to kill with that shot as long as the top of the heart, the aorta above the heart or both lungs are penetrated anywhere close to centrally. I have taken many species of big game with this shot and by far the elephant is the easiest to kill with it. You gain nothing by using a bullet that exits. I have taken a dozen or so cows and bulls with body shots and have never had one go more than 100 yards. I have used mostly RN solids but also a good selection of FN solids. It is a matter of choice but I don't like to give up a shot because there is another ele behind my target animal or the brush is so dense that I can't tell if there is one back there.

465H&H

quote:

Originally posted by raamw:
Correct me if I am wrong, solids are used for maximum penetration,to penetrate body mass, organs blood vessels and break bones. If I use a bullet that goes completely through an animal I stand a greater chance of accomplishing this no matter what the angle, I personally have little interest in a solid that expands a little and does not achieve max penetration, this would be a controlled expansion in my book.

If all bullets tested surpass the required max penetration than #2 on the list would be the cavitation damage
Think of this bullet #1 breaks a front leg runs up along the spine and stops short of the hip/rear legs, no organs hit just muscle damage...that animal is gone

Bullet2 does the same but continues to the rear hip leg area and breaks one or both, he it doing donuts on the ground,and a follow up shot is certain, penetration does matter

Solids are only really necessary for elephant and for body shots on hippo. For buff it is a matter of choice as both will work just fine.

I can guarantee that if you break the front leg of an elephant, it isn't going anywhere, as it can't walk or run on three legs. The bullet will lose enough velocity and momentum that it is highly unlikely to exit the paunch assuming it makes it that far. It surely won't have enough momentum to break a hind leg.

465H&H

quote:

Originally posted by 465H&H:
I seldom disagree with JPK but in this case I have to. I know he will understand.

There is no need for a bullet to exit the side of an elephant on a broadside body shot. Elephants are extremely easy to kill with that shot as long as the top of the heart, the aorta above the heart or both lungs are penetrated anywhere close to centrally. I have taken many species of big game with this shot and by far the elephant is the easiest to kill with it. You gain nothing by using a bullet that exits. I have taken a dozen or so cows and bulls with body shots and have never had one go more than 100 yards. I have used mostly RN solids but also a good selection of FN solids. It is a matter of choice but I don't like to give up a shot because there is another ele behind my target animal or the brush is so dense that I can't tell if there is one back there.

465H&H

We don't disagree. You are right, on eles the first one, at least, doesn't need to and maybe shouldn't exit.

FWIW, I have had .458" 500gr Woodleighs at 2135fps mv exit on cow eles shot broadside and slightly quartering away.

JPK

quote:

Originally posted by JPK:
The same for elephants. If you are willing to take a first shot which is a body shot, you ought to be using bullets which offer pass through capability. the same for all subsequent shots.

On the other hand, if your first shot is going to be a brain shot, and only a brain shot, your first shot needs only adequate penetration to traverse the skull, front to back and side to side, plus about 8" or so in the event your frontal is low, so it can break the joint or spine. That opens up the selection of solids.
JPK

How do you determine which shot before you load the magazine?

On my September hunt in Zim, I shot two elephants. First one was not even the one we were looking for, burst out of the bushes onto the river bed heading at us with some friends. The only shot was a 15 meter frontal and the bullet went through the skull narrowly missing the brain but hitting the spine.

The second one ended up being a quartering shot at 55 meters going through the left shoulder and ending at right hip.

In both cases, being a night hunt, I had only a few seconds to decide on the shot, acquire the target and shoot.

No luxury of deciding prior to the kills which shot to take. So, I had 500gr CEB solids for maximum penetration.