Half year ago I presented in this forum the concept of the "SuperPenetrator".
Topic: Penetration of Solids, Big Bore Forum page 21. address:
http://www.serveroptions.com/ubb/Forum16/HTML/000693.html

Now the SP bullet is optimized for the .458 caliber 500gr at 2350f/s.
It penetrates water soaked paper or water containers in a stable fashion to about 100 inches. Bone equivalent is penetrated up to 30 inches.

The image shows the preferred construction, left copper with ogive and steel front disk, lenght 39 mm. Right bullet is optimized for short lenght to be used in .458 Lott, lead core, lenght 35,5 mm.

Next image shows two designs with conical nose, left copper with steel disk, right integral brass. weight around 440 gr, not further followed.

Next: The 500 gr lead core SP, new. next: recovered from 27 " resin bonded hard board. next: recovered and stopped by a steel plate after passing in stable flight through 95" of water soaked paper.

See also www.grosswildjagd.de - SuperPenetrator

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Great Norbert. Thanks for keeping us updated.

Norbert,
Did you test the shortened design in your .458 Lott, as planned?

Norbert:

You must be right after all. 95" of wet paper. That is some penetration.

I am surpised that the steel disk doesn't deform though.

That must have been what Taylor was using when he shot those five eland and a tree with one shot!

Will

The supercavitating SuperPenetrator WOW!

I'll bet Will would be happy to field test them on some pachyderms for you. I Will volunteer him.

I just got my copy of _Mahohboh_ by Ron Thomson. Notice how I can now properly spell the title and the author's name, meaning "The Great Slayer of Elephants."

This SuperPentrator might also be called the "Mahohboh Bullet."

Good work, keep us posted.

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RAB

For comparisons sake what would a"normal" solid penetrate in the same tests with the same velocities?

Sounds like someone is onto something good...

Mike

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Victory Through Superior Firepower!

Norbert,

I read your article in the Hatari Times and I was very interested that a solid creates a bubble of water vapor in front of it, and the bigger the bubble the deeper the penetration, and the bigger the meplat the bigger the bubble. I may have misunderstood a bit, but that sounded like the gist.

If I understood what you were saying, that is why the GS Custom and the Trophy bonded sledgehammer tend to penetrate deeper than Woodleighs, is that correct?

As for the super penetrator, have you presented it to any of the mainstream bullet makers to see if they will pick it up?

Mike:

>For comparisons sake what would a "normal" solid penetrate in the same tests with the same velocities?
-Water soaked paper or rows of water containers: 30" (1/3 of the SP!)
Special resin bonded hard board as bone equivalent: 32" (10% less)
Also proven on elephants with great succces.

500 grain:

>I read your article in the Hatari Times and I was very interested that a solid creates a bubble of water vapor in front of it, and the bigger the bubble the deeper the penetration, and the bigger the meplat the bigger the bubble.
-You must read: The bigger the cavitation disk, the more stable the flight and as a follow up the deeper the penetration. A simple meplat is not sufficient. The bubble is surrounding the bullet, generated at the front.

>If I understood what you were saying, that is why the GS Custom and the Trophy bonded sledgehammer tend to penetrate deeper than Woodleighs, is that correct?
-At least we can now understand, why some of the modern FN bullets penetrate better than RN. Any solid generates its cavitation bubble and penetrates in increasing order: RN, ogival RN, FN, SuperPenetrator.

>As for the super penetrator, have you presented it to any of the mainstream bullet makers to see if they will pick it up?
-No. I just finished that work. I think this bullet is only useful for elephant hunters and evt. raking shots on buffalo. That means, there is a very limited demand.
But I observe, that small bullet makers try to jump on my train.

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Nick,
>Did you test the shortened design in your .458 Lott, as planned?
-Last october I tested the long copper design in the Lott. The shortened version is very new and will be tested in september.

RAB,
>This SuperPentrator might also be called the "Mahohboh Bullet."
-I think Ron don�t need this kind of bullets. Did you read his "killing an elephant with a knife"?

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Norbert,
Thanks for the tip. I shall look for the knife story.

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RAB

I am still not understanding the physics.

Why is a cavitation disk more effective than a meplat, assuming that both have the same frontal surface area?

What about a concave cup-shaped meplat?

Norbert,

Congratulations.

I am wondering whether I am in the right ballpark in my layman's understanding of supercavitation. I am not trained in fluid dynamics.

Let's say you were trying to protect yourself from an antogonist (let's call him Zero Drift) who was trying to soak you with a garden hose that had a 6 mm nozzle orifice. Let's further say that you were trying to protect yourself with a 45 caliber Woodleigh solid mounted on the end of a narrow stick, I would expect the 6 mm stream of water to follow the contour of the round nose (no cavitation) and get around to the back of the bullet and get you all wet.

If one of your superpenetrators was on the end of that stick, I would expect the stream to be thrown out radially (perpendicular to the bullet axis) so that neither you nor even the sides of the superpenetrator got wet.

If Zero Drift switched to a 45 caliber hose, the Woodleigh would still be no protection, but what about that superpenetrator? The inside 6 mm of that water stream will still be trying to head out radially, but now it is surrounded by a toroid stream extending out to 0.458" that is still moving in your direction. The diverted inner 6 mm of the stream will tend to push the outer part of the stream outward, but what you get is a resultant, the sum of a radial flow and the flow along the bullet axis. The resultant flow will move at an angle outward from the edge of the 6 mm disk on the bullet nose.

If the 6 mm disk is not elevated above the rest of the bullet's ogive, the angled stream could immediately make contact with the ogive and follow the contour of the bullet; and Zero Drift will get you all wet. This is what might happen with a Grand Slam* and this may be what differentiates a penetrator disk from a simple meplat.**

If the 6 mm disk is elevated above an ogive of only 0.5 or 1 calibers, the stream may skip off the edge of the 6 mm disk (I'll assume that the phenomenon whereby some of the bullet is not getting wet is called cavitation), but the angle may not be outward enough to prevent its re-establishing contact with the ogive, and the stream of water will grab hold of the ogive and follow the shank of the bullet back to you, and Zero Drift will again soak you with water.

Tired of getting soaked by Zero Drift, you lengthen and narrow the ogive to 5 calibers, and now the stream of water misses the ogive and shank of the bullet completely. If you are holding the bullet on a long enough stick, you might even avoid getting wet.

Now, Zero Drift understands that this magic bullet you have been trying to protect yourself with is designed for water, but intended for animals that are mostly bigger than the 45 caliber nozzle he's been using on you. What the bullet will be seeing in real life is a stream approximating water (watch them bones) that is effectively infinite in diameter. So let's say he switches to his biggest nozzle he's got, the one on his 2 bore fire hose. No 45 caliber bullet on a stick is going to keep Zero Drift from mercilessly drenching you. However, if we arrange for Saeed to videotape this act of cruelty, we might see out in the middle of that icy cold stream of water, at the end of that stick you're holding in your cold but steady fist a 45 caliber bullet that for the most part is staying dry, all except for that little 6mm disk on the front of it. Is that a fair layman's description of supercavitation?

BTW, what is the speed of sound in water? How about buffalo meat? I know these bullets are supersonic in air, but do they go subsonic immediately when they hit tissue? If they do, could some refinement of the bullet's base help out with stability?

H. C.

*Or, what might happen with a Grand Slam, for part of its path through the target is just what happens with the superpenetrator. Possibly the superpenetrator is just set up to maintain the supercavitated condition for a longer time (greater range of velocities) than a Grand Slam.

**Would someone please tell me how to pronounce meplat?

[This message has been edited by HenryC470 (edited 05-02-2002).]

500grains,
>Why is a cavitation disk more effective than a meplat, assuming that both have the same frontal surface area?
-As far as I got the interpretation of supercavitation from HenryC470, he is right. (my english is at its limits).
It is the exceptional stability of the supercavitation water vapour bubble generated by a protruding disk, which makes such a big effect compared to a meplat. The bubble is a dynamic system, easily affected by disturbing forces. It is the sharp protruding edge where the hydrodynamic flow tears off and is converted to a quasi aerodynamic flow with the least turbulence and contact to the bullet. Behind the meplat, the bubble will collaps after a shorter time. The image is not very sharp, so it is difficult to see the edge at the rear of the disk. I had a problem to develop the short design, because the disk in front of a RN is not sufficient. To compensate for that angle off axis (in fact too big), I found, that another sharp edge at the circumference helps to stabilize the cavitation.

Norbert,

Sorry to be so long winded in that last post. I was trying to illustrate. The beer is wearing off, and I'd like to see if I'm on the right track paraphrasing what you've already said (your link, www.grosswildjagd.de is quite informative):

The flat 6 mm disk throws fluid outward radially, and the force this radial flow exerts on the surrounding fluid is enough to hold it away from the ogive and shank, so the bullet is riding in an envelope of vapor rather than liquid.

If I'm close to correct so far, could you clarify something else for me?

If a 6 mm disk raised above the nose of the superpenetrator causes supercavitation, would not a 45 caliber disk do so even more? This is what you would have in case of a 0.458" bronze wadcutter.

I'm guessing the wadcutter would be more supercavitated than the superpenerator with its 6 mm disk.

I'm also guessing that the superpenetrator is still superior to the wadcutter.

The wadcutter probably throws more liquid out radially than is necessary for the vapor bubble to completely surround the entire bullet. The extra unnecessary work the wadcutter does throwing fluid outward slows it down and decreases penetration. In other words, the wadcutter is effective (at supercavitating), but inefficient.

Going the other way, and you've probably tried this, a disk much smaller than 6 mm will not throw enough fluid out radially to create a vapor bubble big enough to surround the entire bullet. The vapor bubble will collapse onto the shank of the bullet, increasing drag and decreasing penetration. In the limit of a small diameter penetrator disk, you are back to having a round nose bullet. A disk too small becomes ineffective where a disk too large was inefficient.

Somewhere, probably around 6 mm, you have the optimal disk diameter for a 500 grain, 45 caliber bullet.

Is that about right?

H. C.

[This message has been edited by HenryC470 (edited 05-02-2002).]

[This message has been edited by HenryC470 (edited 05-02-2002).]

H.C. :

>The flat 6 mm disk throws fluid outward radially, and the force this radial flow exerts on the surrounding fluid is enough to hold it away from the ogive and shank,

-The correct mechanism is: the fluid accelerates at the edges and the hydrostatic pressure decreases (remember Bernoulli�s law) so the water will evaporate.

>so the bullet is riding in an envelope of vapor rather than liquid.

-correct. But the water from a garden hose has not sufficient velocity to start a cavitation. Minimumm is 100 miles per hour. BTW: The "disk on a stick" is used with some (experimental?) warfare heads.

>If a 6 mm disk raised above the nose of the superpenetrator causes supercavitation, would not a 45 caliber disk do so even more?

>Not more, but it guaranties a stable supercavitation. But than you observe of course an increasing resistance against the tissue at the front of the bullet, which decreases penetration. So you have to find a compromise. You also have to maintain sufficient energy dissipation. For the .458 500gr at 2350 f/s the optimum diameter is 7.2 mm. 3 times penetration in tissue, 10 to 20 % less penetration in bone. A too small diameter will result also in ample penetration, but not enough energy delivery and with a peripherial brainshot it may take some seconds to kill the animal. The wound channel is smaller than with blunter noses.

>I'm guessing the wadcutter would be more supercavitated than the superpenerator with its 6 mm disk.
-but with no pay off in penetration.

>Going the other way, and you've probably tried this, a disk much smaller than 6 mm will not throw enough fluid out radially to create a vapor bubble big enough to surround the entire bullet. The vapor bubble will collapse onto the shank of the bullet, increasing drag and decreasing penetration.

-It works, provided the head is slender enough with a very small angle off the axis.

>Somewhere, probably around 6 mm, you have the optimal disk diameter for a 500 grain, 45 caliber bullet.
-7 to 7.5 mm for 2350 f/s. For the right design of the head, it is about 40% of the caliber cross section.

If someone is interested in more info about supercavitation war heads, look at:
www.sciam.com/2001/0501issue/0501ashley.html

Norbert

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[This message has been edited by Norbert (edited 05-02-2002).]

Norbert,

Thanks that'll be very useful for my .450 Ackley mag.

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BER007
Keep the faith in any circumstances
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BBER007@HOTMAIL.COM

Norbert,

Have you talked with Gerard about making some of these? If he made a run in 416 or 458 diameter you'd likely get a lot of test data quickly.

I am a fan of the WideFlatNose LBT bullet design. I suspect that they generally work on the same principle as your SuperPenetrator.

I understand how the sharp edge promotes separation of flow and reduces pressure below the vapor point. I am sure this works reliably in water and water-filled tissue, but I expect the edge will get wiped off quickly in drier media or bone. Since it would then act as a WFN, this is not a bad "failure mode"!

Gerard really likes high BC, which I am sure these bullets do not exhibit. Have you compared the BC between the SP and a WFN of same meplat?

Don

Don,

>I am a fan of the WideFlatNose LBT bullet design. I suspect that they generally work on the same principle as your SuperPenetrator.
-I don�t know how they look like. It�s a handgun bullet?

>I expect the edge will get wiped off quickly in drier media or bone. Since it would then act as a WFN, this is not a bad "failure mode"!
-As you can see above, the edges are preserved in harder materials and bone. As a spin off I have a armour piercing design which whizzes through metallic targets like butter.

>Have you compared the BC between the SP and a WFN of same meplat?
-I haven�t measured the BC up to now, but it is not very different from other blunt or round nose bullets. The POI at 100 yards is not too much different.

Norbert

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Norbert, since the penetration efficiency is so much higher have you investigated what performance you can get with lighter weight bullets, such as 350 to 400 grains, at similar velocities (2100 to 2300 fps)? What would interest me is a moderate weight design that gave very good soft tissue wounding characteristics with a penetration of 30 inches in paper (2/3 typical solid, but twice typical softpoint).

Harald,

quote:

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..have you investigated what performance you can get with lighter weight bullets, such as 350 to 400 grains, at similar velocities (2100 to 2300 fps)?.. with a penetration of 30 inches in paper (2/3 typical solid, but twice typical softpoint)

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not systematically, but a 400 gr with a 8.5 mm disk was near those figures.
Norbert

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How well do these things fly? How accurate are they, relatively speaking, compared to other bullets of similar weights and calibers?

Interesting innovation.

Russ

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"Out here, 'due process' is a bullet!" -- John Wayne, "The Green Berets"

Norbert,

1. What kind of metal alloy do you think is best to make the bullets from?

2. Is that alloy intended to deform as GS Custom FN solids do at high velocity, or do you intend no deformation, as in the case of a Barnes or Woodleigh solid?

3. Is there any chance of ordering some of these bullets in .585 and .510 caliber?

If someone will make some up, I'd LOVE to play with them. (I'm a physics nerd, too...)

Calibers I'd be most interested in are .308, .375, and .458.

Pertinax

Norbert, you have aroused my curiousity. Where would I be able to get some of these bullets? I would love to try some in my 450 Ackley. Thanks. - Dan

Russ,

there is no essential difference in exterior ballistics to conventional RN solids. POI at 100 yards is about the same. BCs are not available yet, too many layouts used.

500grains,

in no case is any deformation intended when using for animals. For optimum results the dimensions of the whole nose design is very critical.
Best material is the copper body with steel insert or the integral design from MS 72, that is brass from 72 % copper.

pertinax and Dan,

the SP bullets are not available at the moment. I just finished the experiments on test targets for the .458 caliber and will test them further on elephant and buffalo soon.

Norbert

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Thanks Norbert. Please keep us posted. Take care - Dan

Thanks Norbert.

Due to the difficulty I am having getting my GS Custom bullet order, I am tempted to get a lathe and make my own. But if I do so, I think I should use the integral super cavitator design.

What do you think?

Norbert--do I understand correctly, that the SP bullet design could allow lighter bullets with less section density the same penetration as heavier bullets in the same caliber, with out the penalty of increased recoil energy.
Example: a .500 cal 525 gr bullet with less than 0.3 section density and PI of approx 90 can be given the same penetration using SP as a 700 gr bullet, only at lower energy.
Could this concept be possible?????????

Big Bores should be fun! pmm

500grains,
for a do-it-yourself made SP bullet the integral conical brass design is the most suitable. It is not the best performer with respect to the supercavitation, but the other designs are evtl. too difficult and critical to produce with a normal lathe.

Paul,

quote:

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--do I understand correctly, that the SP bullet design could allow lighter bullets with less section density the same penetration as heavier bullets in the same caliber, with out the penalty of increased recoil energy.
Could this concept be possible?

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That is not the intention of the SP design. It is possible, if the lighter bullet is SP and the heavier is conventional, but with no trade off in wounding capacity. The SP bullet has its merits with the heavy for caliber bullets, which in tissue may become instable. It overruns the PI concept, which is governed by the decelerating forces. The SP gets its penetration from stabilisation of its travel through the tissue.
We learned from these experiments, that we observe two different mechanisms of penetration in animals: 1) The penetration in aqueous tissue (muscles, organs), limited by the stabilisation of the bullets travel and 2) the penetration in bone, hide and sinews, limited by the forces acting on the bullet, (friction, shear resistance, viscosity).

BTW, that is the difference between shooting in water soaked paper or plywood..

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