Excellent! Since we have both sons of Shadow present...how's about giving us your collective view on the application of Schrodingers Equation ( the time dependant version ) as it applies to the deformation of material DURING impact. If you don't mind let us have the solution with variations in spin included. A graphical representation would be helpful...

You've got me there. The detail escapes me. All, I know for sure is that the time dependent version would differ from the time dependant version.

quote:

Originally posted by Warrior:

quote:

FN favors velocity and that is also why a lighter, faster FN can out penetrate both a heavier RN and a heavier FN.

Get the RN out of the equation - it is an apples and pears comparison.

The heavier FN , typically the bullet with more momentum will win every time, even though its velocity is lower. That proves that velocity is not favoured in the FN bullet. Velocity is not the ability to do any work (Velocity is merely distance over time). Velocity is a "single item" that you pull out of context, as it has to work with a few other key variables to have any meaning, like mass, form or SD and nose shape. Velocity on its own has no meaning. Go do the tests and come back to us, then we talk again.

So my position is still as before ... and I quote ... "I take issue with the statement that a lighter FN bullet is favoured by higher velocity over a heavier FN bullet at lower velocity. And this I have made clear, as I pointed out that it is hardly possible in our current ballistic model. However if the same momentum value can be achieved by both bullets, then penetration could be equal provided in-target drag is the same, but this rarely happens, as higher velocity invariable creates higher stagnation pressure and causes more drag. That is why the higher momentum bullet at lower velocity will out-penetrate the lower momentum bullet. Thus, we cannot say that velocity as a sole factor favours penetration with a FN bullet – it is not correct. Velocity is not a force on its own."



Warrior

You have it backward, it is the FN's shape which reduced drag and the higher the velocity the more the drag is reduced. See again RIP's results. If this were not the case, regarding the FN shape reducing drag, then the equal weight, equal speed, round nose, with equal momentum and energy would penetrate equally with the FN, but it does not.

Or take it one step further, the only way that a lighter FN can equal the penetration of a heavier RN, with more momentum and more energy, is through reduced drag.

RIP's test confirm that greater velocity further reduces FN drag, or the heavier bullet would have penetrated more, but it was a push.

JPK

J/

Reduced "drag" in the FN is an artifact of cavitation not a function of it's Cd. The RN will have a lower Cd if neither cavitates.

I have done my best to keep my nose out of this because I know where this is going, but anyway!

In my test work and field work-can't attest to anyone else.

1. A. Same FN Solid--Same Medium--Same Rifle--Different impact velocity.
Bullet #1 Impact velocity 2450 fps Bullet #2 Impact veloctiy 2130 fps
Bullet #2 penetrates 12% deeper than bullet #1. Both bullets stable and dead straight penetration.

B. Same FN Solid--Same Medium--Same Rifle--Different Impact Velocity.
Bullet #1 Impact Velocity 2140 fps Bullet #2 impact Velocity 1819 fps
Bullet #1 penetrates 24% deeper than bullet #2

Conclusion; There is a sweet spot concerning velocity/penetration of a solid that does not deform and is stable. This has been a contention for a long time in many circles, but not all, for what I have tested and seen there seems to be a place between 2000 and upwards of 2400 fps that is optimum. Most of the time when I go to the field I am in that spot between 2100 and 2250 fps. Fact or not? It is a fact in my test work, and what I have done in the field. I cannot attest to others, nor dispute. Nor will I argue about it. My test work is repeatable time after time. It is possible that different medium can show a different result, I will not dispute other viable tests--these are the facts concerning mine only. For instance one may take a smaller caliber at high velocity and if nose profile is equal it might be possible the smaller caliber could penetrate deeper than a larger caliber at slower velocity? This is something I cannot attest to, as I have not tested as of yet, but do have it slated to be tested at some point. It is my contention that two bullets of the same type and caliber, one at high velocity one at lower velocity that the higher velocity bullet expends a tremendous amount of energy during the first 20%-40% of it's penetration, and expends so much energy on the target that it is slowed down considerably quicker than a bullet at a lower velocity that does not expend so much energy up front. This is something I cannot prove beyond doubt with the equipment I have currently, but based on my observations of the test medium and it's condition I do believe this to be true.

Nose Profile-Sectional Density-Twist Rate?

Time after time after time a FN bullet penetrates straighter-and deeper than any RN designed bullet.

A FN design solid that is lighter than a RN design bullet-EXAMPLE 450 gr FN Solid at 2150 fps---500 gr RN Woodleigh at 2150 fps---The lighter FN bullet will out penetrate the RN heavier bullet every single time, on average around 30% deeper.

Two same design bullets--Example 450 FN Solid at 2150 fps-500 gr FN Solid at 2150 fps the 500 gr FN bullet will out penetrate the 450 every single time.

Two same design bullets-Example 450 FN Solid at 2250 fps-500 FN Solid at 2150 fps, the 500 gr FN bullet will out penetrate the 450 every single time.

Two different design bullets twist rate too slow to stabilize RN--Example 1:18 twist rate .500 caliber-512 gr RN Solid 2048 fps-510 FN Solid 2030 fps--512 RN stable to only 60% of it's total penetration--510 FN Solid stable to 90% of it's total penetration which was 58% deeper than the RN Solid. Same test with a barrel at 1:12 twist stabilized the 512 RN to 91% of it's total penetration and the 510 FN was 100% stable for the entire depth of it's penetration. At 1:12 the 510 FN still penetrated 32% deeper than the 512 RN solid.

Conclusion; Nose profile is everything when contemplating straight deep penetration. Nose profile can overcome sectional density and even too slow twist rates. When two exact same nose profiles are used, but different weights in the same caliber the heavier bullet wins in the penetration department, thus proving sectional density. Twist rate is extremely important with RN Solid designs but not as much with a FN Solid.

Personally I rely on a solid bullet to drill deep straight holes. I do not want this bullet to deform, expand, bend, rivet, break, in any way. There is no possible way that a solid that deforms, expands, bends, rivets or breaks can possible penetrate as deep as the same bullet that does not deform, expand, bend, rivet, or breaks! If said bullet has to be slowed down to prevent deformation, expansion, bending, riveting, or breaking then so be it, slow it down, penetration increases. If I wanted a bullet that would deform or expand I would choose an expanding bullet.

OK take your shots!
Michael

Not much one could disagree with here. Only to add:
When correctly designed, expansion in a solid is not a liability. It is an advantage because it prevents bending, breaking and tumbling. Drive any solid fast enough and it will deform. Correctly made solids don't need brakes, run them as hard as you like and they will not fail you. One less thing to fret about.

Michael. Well said. I couldnt agree more, just my words...

I don't see any need to run bullets over 2,300 fps for dangerous game. Unless your Saeed you don't shoot dangerous game over about 100 yds except in the unlikely case of an escaping wounded animal. Velocities over this level just stress bullets too much for no gain in penetration. Go to a heavier bullet and be happy!

465H&H

quote:

I don't see any need to run bullets over 2,300 fps for dangerous game.

What about the man who only has a 375H&H, 378Weatherby or 416 Rigby / Remington? Anything at 2300fps or less, from those calibers, puts a serious crimp on the capability of the caliber.

quote:

Velocities over this level just stress bullets too much for no gain in penetration.

Not true unless you are making that concession to bullets that are not capable. See my link above to 470Mbogo fact or fiction.

quote:

Go to a heavier bullet and be happy!

Not required if you use the right mono solid. Heavier bullets and the slower powder they ask for, increase recoil. Why break a gun in the first place and why risk that breakage at a critical time?

quote:

Originally posted by Gerard:

quote:

I don't see any need to run bullets over 2,300 fps for dangerous game.

What about the man who only has a 375H&H, 378Weatherby or 416 Rigby / Remington? Anything at 2300fps or less, from those calibers, puts a serious crimp on the capability of the caliber.

quote:

Velocities over this level just stress bullets too much for no gain in penetration.

Not true unless you are making that concession to bullets that are not capable. See my link above to 470Mbogo fact or fiction.

quote:

Go to a heavier bullet and be happy!

Not required if you use the right mono solid. Heavier bullets and the slower powder they ask for, increase recoil. Why break a gun in the first place and why risk that breakage at a critical time?

Added velocity is still not necessary, better to go with a 350 grain bullet in the 375s and a 450 grrain in the 416s. Why would a lower velocity or heavier bullet break a gun? The heavier recoil whether from more bullet weight or added velocity would be nearly a wash.

465H&H

quote:

You have it backward, it is the FN's shape which reduced drag and the higher the velocity the more the drag is reduced.

JPK,

There is mud on your windscreen.
Hopefully after Alfs's explanation you will change your position.

Warrior

465H&H,

To reduce recoil, the principle is to go to lighter, faster bullets and faster powder. Any way you look at it, a 450gr bullet from a 416 Rem Mag will have about 10% more recoil than a 380gr bullet. Shooting a rifle at 10% more recoil increases the risk of breakage by much more than 10%. Ask anyone who repairs them - I have been doing so since 1979.

If you calculate recoil energy, speed and impulse with a recoil calculator, there is little difference between light and fast / slow and heavy, but recoil calculators do not take into account muzzle pressure. That is where recoil is generated and not the insignificant little numbers generated by recoil calculators.

A quick way to shortening the life span of the stock and optics of a rifle, is shooting it with heavy for caliber bullets.

quote:

Originally posted by Warrior:

quote:

You have it backward, it is the FN's shape which reduced drag and the higher the velocity the more the drag is reduced.

JPK,

There is mud on your windscreen.
Hopefully after Alfs's explanation you will change your position.

Warrior

Macifjef answered both your misses. Neither your nor Alf believe in cavitation, which must exists if a RN and a FN both penetrate without tumbling, since the FN will penetrate more. And it will do so though it has less mass, less momentum, less energy but more or even just equal volocity.

If you want to see your theory actually work, you need to try it in a dry box with wood dividers. See Andy's experiments for instance. The RN with momentum alsways penetrates more according to his data. But we know that a FN lacking momentum and energy will equal or exceed the penetration of a RN is tissue. Why? Cavitation. Cavitation reduces drag.

JPK

JPK,

Watch for Warrior/Truvelloshooter/Chris Bek to start repeating his variety of conflicting murkinii about now, in the hope that some of them will become true.

/

This may be preaching to the choir but flat noses were the SINGLE DECISIVE feature to provide straight stable penetration in my tests in saltwater.

A old style Barnes RN Mono with a basal cavity calculated to move the center of mass forward of the center of form failed in exactly the same manner as an unmodified RN. Another Barnes RN Mono with bands cut in the base calculated to move COM forward of the COF failed also. Once I cut a small meplat on a Barnes - BINGO, a straight penetrating projectile.

quote:

Neither your nor Alf believe in cavitation

Holy shit, you are drifing off the map of the earth. It is not even mis-quoting, it is fabrication to obscure the real debate !!!




Warrior

quote:

Cavitation reduces drag.

Warrior

quote:

it is fabrication to obscure the real debate !!!

I forgot about the "fabrication to obscure" card. How could I, you use it so regularly.

From your confusion
disbelief
and rejection

of "cavitation reduces drag", I take it that you are firmly of the opinion that cavitation does not reduce drag?

Despite what Mac told you:

quote:

Reduced "drag" in the FN is an artifact of cavitation not a function of it's Cd. The RN will have a lower Cd if neither cavitates.

Despite what you have said yourself but probably forgot because it was four days ago:

quote:

2.)at the very same velocity the FN Solid will out-penetrate the RN Solid. That has to do with geometry and not velocity.

Despite JPK pointing out the obvious to you:

quote:

the only way that a lighter FN can equal the penetration of a heavier RN, with more momentum and more energy, is through reduced drag.

.............you really believe that cavitation does not reduce drag?

Maybe you should give us your definition of "cavitation". I will bet it is different from mine.

/

Gerard you are getting no further responses from me. It leads nowhere.
I have already stopped replying to your previous post with its snide remarks - a waste of time, as always.

Warrior

So you want to dish it out, but you don't want to take it and the easy way out is to make some excuse and run.

The basic problem here is that we are talking about two different things when we discuss cavitation. The terminology used is not clear to all.

A. Cavitation and supercavitation are related.

B. Cavitation and cavity formation, permanent cavity, temporary cavity, primary cavity and secondary cavity are related.

When someone talks about one, the other is presumed and when definitions are asked for, just because you are stuck in rut B and cannot imagine that someone could differ from you, or you think you know better, you throw your toys and go home.

Let us be clear about what we mean when we talk cavitation:

1. The correct definition relates to the formation of bubbles (vapor) in a fluid or soft solid, when the edge form and the flow speed over that edge creates the condition.

2. Cavitation is also used to denote cavity formation and that use is incorrect.

Two very different things, in any case.

If we stick to correct terminology, or at least explain ourselves more adequately, much of this unpleasantness will be avoided. It also helps if we admit to murkiness on some subjects and learn from one another.

Photographic representation of definition #2

/

quote:

The assumption made here on AR by many is that the vapour bubble formation in a fluid is a function of nose shape.

Their assumption in a general sense would be accurate. Cavitation or "super-cavitation" is a function of an objects shape and how it moves through a fluid. What shape produces how much cavitation and whether it is beneficial is another question. I doubt anyone posting here or anyone producing bullets for the civilian market has access to the software needed to optimize that equation. Maybe you know someone who does advanced design work in hydrodynamics (propellers) ...??

quote:

smaller diameter projectile because it's TIP FORCE is going to be less

Yeeees Indeedy!! So how would you translate "tip force" into penetration resistance ..?? Area decrease inverse to material resistance or increase in penetrater energy..??

quote:

In solids the resistance to penetration is independent of velocity, it remains constant in solids whilst in fluids the resistance is related to the square of the velocity

Yep! Resistance to penetration is constant IF the material doing the resisting is constant AND the velocity is constant. Penetration of a solid increases with velocity of the penetrator. So then back to Warriors obsession ...is penetration a function of momentum or energy ...???

Guys just a Q:

does a size of an area that a bullet actually touch the tissue with, has any impact - i.e. with spherical RN the area (1/2 sphere) is roughly twice the size of the FN area (circle)?

Gerard

At what velocity would you estimate penetration to be best for your FN bullets.
At high vel they will expand to some degree and that will reduce penetration, so what is the optimal vel for max penetration?

Alf,
My take on this is that there is not a simple way of looking at how and why an FN of a specific configuration works better than other shapes, be they round-nose, flattened round-nose or whatever.

Every aspect of solid design is questioned as questionable by someone. Every design element has its proponents and opponents. Somewhere someone says cavitation, shoulder stabilisation, dart stabilisation, spin stabilisation, round-nose design, flat-nose design, steel jacket, brass mono and copper mono works/does not work.

You say that cavitation in fluids is ok but that it does not happen in tissue. All I can say is that I do not have enough science to say you are wrong. I can also say that, when one design element is changed at a time, certain positive or negative results come about. Do enough "tuning" of the design and, eventually, the individual negative results reduce to such a small number that, overall, the result remains positive and the bullet has the highest reliability.

Certain obvious parameters and absolutes are present with solids. The bullet must not shed weight, it must go as deep as possible and it must maintain as straight a path as possible.

Design elements that work against these parameters must be avoided and elements that promote these parameters must be explored to their limits and retained.

In practise I see that momentum and cross sectional area are related when penetration depth is considered with softs.

I also see that it seems not to matter with solids when certain design elements are present. Is this logical? No it is not, so in casting about to explain this to myself, I find that MacPherson and a fluid engineer from a large local industry seem to be in agreement. There is a theory that fits. Are they right? MacPherson has a depth of background and research that is very impressive and the fluid engineer has so many degrees I am amazed that he is not 100 years old already. Who knows - I don't - but they have the best explanation. So until someone comes along with a better theory, I have to believe them.

One rule I have come to accept: I do not care what old wives tales people believe are true. Observation of actual result takes preference over theory every time.

Case in question right now: "Solids bullets should not deform."

I see that, in real life, all solids deform - no exceptions.
I see that when they deform in a certain way, bad results happen.
I see that when they deform in another certain way, they continue to perform well.
I see that when I design for prevention of deformation, it cannot be done.
I see that it is possible to design for control of deformation.

There is no easy way to say this and I do not want to offend, but I would be stupid if I continued to adhere to the belief that solids should not deform. It is a pipe dream and better to accept reality and design to accomodate that reality. I think GSC has found a solution and I think I can explain why it is a solution. The theories I see presented, seem to fit reality.

mouse93,
Yes, the total area facing the direction of travel determines in part the resistance to motion.

buffalo,
I know this sounds illogical, but it does not matter what speed is used with agiven FN. Penetration depth in water/plywood buffalo simulant and the big five does not vary significantly with speed. Absurd comparisons in this regard excepted - 100fps will obviously not be as good as 2500fps. This was shown here by the testing that RIP did (thank you Ron for that body of work, I know what it takes and we all appreciate it). In 375 caliber, varying the speed and weight over a range of several hundred fps and from 270gr to 300gr, did not materially affect penetration depth. Only the total amount of damage was observed to be different.

In a purely wood stop box, penetration is significantly enhanced by speed. This was done by 470Mbogo and we owe him for contributing to our collective experience also.

Andy has also done much work on all types of media and he is either a glutton for punishment or he enjoys it. Either way - thank you!

The bottom line is: If the bullet is an FN shape, speed ads to the total destruction in a positive manner, every time.

This is why we make experience based recommendations for GSC FN bullets. That has always been: Use the length (weight) bullet we recommend and run it as fast as what is safe for your circumstances and shooting platform. We place reliable, repeatable performance at the head of our requirement list. We see no use for a product that will deliver miraculous performance one time and fail miserably on the next shot.