Same Ft/Lbs at 500 yards, is heavier grain bullet more effective?

406Smith

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How energy causes bullet expansion (based on well known real life science, not marketing materials):

Work-Energy Relationship
41E3B969-CA3B-4974-97B7-3B9B99833555.jpeg

How Work is related to Force:
205FED8D-7490-4C95-9D76-87D752E678DB.jpeg

How Forces are related to stress:
E1DE7174-1BE4-493D-A682-42B4C82F9B86.jpeg

Stress-Strain relationship
3D394156-6ED8-4982-8F73-A88EBCD96859.jpeg


 

tpicou

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Formidilosus

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Yeah it is always baffling when people say energy doesn't matter when you consider physics.

Yes, energy exists. So tell me how to use that number? What does “X” amount of ft-lbs of energy tell me about terminal ballistics and killing animals?

Without cross referencing anything what’s the answer to this-

How many ft-lbs of energy does a .308 180gr Accubond need to expand? How about a .277 130gr Partition? .284 180gr ELD-M? .264 130gr TLR? .243 105gr Berger? .223 77gr TMK? .338 225gr TSX?
 

tpicou

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Yes, energy exists. So tell me how to use that number? What does “X” amount of ft-lbs of energy tell me about terminal ballistics and killing animals?

Without cross referencing anything what’s the answer to this-
What does x amount of velocity tell you wrt terminal ballistics and killing an animal? What does y mass tell you? What does z bullet construction tell you? Alone, nothing tells you anything. Your question is nonsensical.
 

wrhoads

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These discussions are always so productive.

'Kill' is a pretty broad definition. A better question might be which one produces a wider and longer wound channel.

Energy and Velocity can tell us very little if we don't know the construction of the bullet. Jacket thickness, lead and jacket hardness, and shape of the bullet all come into play.
 

Formidilosus

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What does x amount of velocity tell you wrt terminal ballistics and killing an animal? What does y mass tell you? What does z bullet construction tell you? Alone, nothing tells you anything. Your question is nonsensical.

No, it’s not.

Those manufactures design and engineer projectiles to work within a certain velocity window. Most bullets will get decent upset/expansion at 2,000fps impact. Expansion of more than caliber diameter for the above bullets are +/-, in order, 1,800fps/1,750/1,700/ 2,000/1,850/1,700/2,200 fps impact speeds. And, for most of them, that is consistent across the whole bullet line regardless of caliber. The Ft-lbs of energy is all over the map for those impact speeds, yet wounds for like bullets are very similar.

There is no available math equation that can tell you how deep a bullet will penetrate, nor how wide the wound will be, nor the shape of it. If you want to know that, you have to shoot that bullet into tissue or properly calibrated tissue simulate at varying impact velocities. Varying impact velocities: not varying impact ft-lbs of energy.
A .308 200gr Partition at 2,800fps impact, and a .243 95gr Partition at 2,800fps impact have vastly different ft-lbs of energy, yet both are designed to work correctly at the same speed, and wounds will be similar- with the 95gr looking like a smaller version of the 200gr.

There is not one bullet from any major manufacturer that is designed around a certain ft-lbs of energy. They are 100% designed around a velocity window and then almost all are engineered to penetrate and expand a certain way in that velocity window in calibrated 10% ballistics gel.
 

tpicou

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These discussions are always so productive.

'Kill' is a pretty broad definition. A better question might be which one produces a wider and longer wound channel.

Energy and Velocity can tell us very little if we don't know the construction of the bullet. Jacket thickness, lead and jacket hardness, and shape of the bullet all come into play.
Exactly. And not just bullet material but also the material properties of what the bullet is entering and encounters along the way. There is a reason finite element modeling exists and that's because in order to answer complex physical questions you need more than just a single value that you read on a box.

Edit: And I should say, when a company says their bullet expands at a certain velocity it's because "velocity" is the easiest/simplest thing for the end user to quantify. It is NOT because that's the only thing that matters.
 

tpicou

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No, it’s not.

Those manufactures design and engineer projectiles to work within a certain velocity window. Most bullets will get decent upset/expansion at 2,000fps impact. Expansion of more than caliber diameter for the above bullets are +/-, in order, 1,800fps/1,750/1,700/ 2,000/1,850/1,700/2,200 fps impact speeds. And, for most of them, that is consistent across the whole bullet line regardless of caliber. The Ft-lbs of energy is all over the map for those impact speeds, yet wounds for like bullets are very similar.

There is no available math equation that can tell you how deep a bullet will penetrate, nor how wide the wound will be, nor the shape of it. If you want to know that, you have to shoot that bullet into tissue or properly calibrated tissue simulate at varying impact velocities. Varying impact velocities: not varying impact ft-lbs of energy.
A .308 200gr Partition at 2,800fps impact, and a .243 95gr Partition at 2,800fps impact have vastly different ft-lbs of energy, yet both are designed to work correctly at the same speed, and wounds will be similar- with the 95gr looking like a smaller version of the 200gr.

There is not one bullet from any major manufacturer that is designed around a certain ft-lbs of energy. They are 100% designed around a velocity window and then almost all are engineered to penetrate and expand a certain way in that velocity window in calibrated 10% ballistics gel.
"There is no available math equation that can tell you how deep a bullet will penetrate, nor how wide the wound will be, nor the shape of it. If you want to know that, you have to shoot that bullet into tissue or properly calibrated tissue simulate at varying impact velocities"

No, you can certainly model it using multiphysics software and I would seriously bet that the companies who design bullets do this before they spend time manufacturing anything. So there literally are math equations that handle it, or you couldn't model it.

"There is not one bullet from any major manufacturer that is designed around a certain ft-lbs of energy. "

Again, they probably model everything. If they don't, what on earth are they doing? At work we model everything from the fluid dynamics in our systems to the structural mechanics of the systems themselves. Similarly we model how blasts affect tissues. It would be malpractice to blindly test or design things.

The speed you keep talking is just a part of what goes into making those bullets act the way they do. That's just how it physically works. I don't know what else to say.
 
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Formidilosus

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No, you can certainly model it using multiphysics software and I would seriously bet that the companies who design bullets do this before they spend time manufacturing anything. So there literally are math equations that handle it, or you couldn't model it.


So is the “multiphysics software” readily available, and what has been your experience in the correlation of what it outputs versus what was seen in animals?



"There is not one bullet from any major manufacturer that is designed around a certain ft-lbs of energy. "


Again, they probably model everything.

I’m not guessing what they do.

Yes everything is modeled, no you aren’t using a bullet that was modeled as to what it will do in tissue and then packaged in a box to be sold. That bullet was tested in tissue, or now for the most part in tissue simulate. Very often, the “model” was not correct and the projectile had to be tweaked.


Using them as an example because there is a large body of work publicly available, the FBI Terminal Ballistics Section is the largest, best researched, peer reviewed, and best funded ballistics lab in the world. They are also the only closed loop ballistics entity that exists. Every research project and study has consistently resulted in the finding that ft-lbs of energy is not a wounding mechanism and can not and will not tell you what kind of damage to expect in tissue.


There are two broad categories- math based metrics, and damage based metrics. Math based metrics give absolutely no functional information to the user- it’s numbers that do not tell someone what to expect in tissue. Damage based metrics on the other hand, literally show you what to expect in tissue- how deep, how wide, and the shape of damaged tissue.
 

wrhoads

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Exactly. And not just bullet material but also the material properties of what the bullet is entering and encounters along the way. There is a reason finite element modeling exists and that's because in order to answer complex physical questions you need more than just a single value that you read on a box.

Edit: And I should say, when a company says their bullet expands at a certain velocity it's because "velocity" is the easiest/simplest thing for the end user to quantify. It is NOT because that's the only thing that matters.

"There is no available math equation that can tell you how deep a bullet will penetrate, nor how wide the wound will be, nor the shape of it. If you want to know that, you have to shoot that bullet into tissue or properly calibrated tissue simulate at varying impact velocities"

No, you can certainly model it using multiphysics software and I would seriously bet that the companies who design bullets do this before they spend time manufacturing anything. So there literally are math equations that handle it, or you couldn't model it.

"There is not one bullet from any major manufacturer that is designed around a certain ft-lbs of energy. "

Again, they probably model everything. If they don't, what on earth are they doing? At work we model everything from the fluid dynamics in our systems to the structural mechanics of the systems themselves. Similarly we model how blasts affect tissues. It would be malpractice to blindly test or design things.

The speed you keep talking is just a part of what goes into making those bullets act the way they do. That's just how it physically works. I don't know what else to say.
FEA is beyond the capabilities of the average joe (wish I had the software and data for these types of discussions), so all we have to go off of is the manufacturers' velocity window. It's not that energy isn't important, but unless manufacturers start offering energy spreadsheets for each product line and caliber it is kinda useless in making a decision on what will and won't work.

It doesn't help that some bullet designs offer different wound channels and each hunter has their own preference on how bullets should perform.
 

Yotekiller

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Seen this on another forum. I can agree with most of it.

 

Crghss

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Long read but a good one. Agree with most of it.

Been shooting 264 win mag using 100/120 gr bullets for 30 years. Don’t ever remember a deer or Antelope taking a step after shooting them in the lungs. All under 200 yds most around 100.

Like the article states the hydrostatic shock incapacitated them then death soon followed. Guess I never really thought about it, just thought they died from shock trauma.
 

tpicou

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So is the “multiphysics software” readily available, and what has been your experience in the correlation of what it outputs versus what was seen in animals?





I’m not guessing what they do.

Yes everything is modeled, no you aren’t using a bullet that was modeled as to what it will do in tissue and then packaged in a box to be sold. That bullet was tested in tissue, or now for the most part in tissue simulate. Very often, the “model” was not correct and the projectile had to be tweaked.


Using them as an example because there is a large body of work publicly available, the FBI Terminal Ballistics Section is the largest, best researched, peer reviewed, and best funded ballistics lab in the world. They are also the only closed loop ballistics entity that exists. Every research project and study has consistently resulted in the finding that ft-lbs of energy is not a wounding mechanism and can not and will not tell you what kind of damage to expect in tissue.


There are two broad categories- math based metrics, and damage based metrics. Math based metrics give absolutely no functional information to the user- it’s numbers that do not tell someone what to expect in tissue. Damage based metrics on the other hand, literally show you what to expect in tissue- how deep, how wide, and the shape of damaged tissue.
Software like COMSOL is readily available if you have the money, yes. We model other types of tissue interactions for stuff like blast propagation and tissue damage and find that it is pretty accurate. Not perfect, of course, but close enough to understand what’s happening. It’s difficult to recapitulate most things experimentally as well, though. An example of that is how a phantom (like ballistics gel) isn’t a perfect analog for tissue either but it is a good enough approximation for certain types. I have thought about doing ballistic modeling, though, because it could be fun (just time and resource intensive)!

My whole point isn’t that kinetic energy is the only thing you should worry about. My point is that what makes a bullet expand is more than just velocity. Specifically the point at which a projectile starts acting more like a fluid and less like a solid as it deforms (dynamic pressures are important pieces here and are really just kinetic energy per unit volume), the relationship between expansion and penetration, and everything else that terminal ballistics comprises. Basically, saying that energy doesn’t matter is false, because it does. A lot of things matter and all of those contribute to tissue damage, including the tissue properties themselves.

Again, I’m not saying velocity isn’t important because it obviously is. For whatever their test material is, the velocities listed are the minimum (or range) at which their projectiles start to deform upon impact. That range will naturally change depending on the material, though, and entering a mouse will differ from an elephant. And, importantly, that velocity range is the easiest thing for the end user to look at when they want to know if a projectile will function as advertised.

tl;dr Saying something doesn’t matter is just a pet peeve of mine because stuff is complex 😜
 

JFK

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Most of what has been said is above my head. Interesting for sure, but probably overthinking it for the average guy going hunting. My experience tells me velocity is #1, weight of bullet is #2. I’m sure ft/lbs are a thing but I’ve just never paid it much attention to it. I’ve moved from 150gr, to 130gr to 110gr bullets in my 270 and stuff keeps dying faster. That tells me all I need to know without math equations.
 

Formidilosus

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Again, I’m not saying velocity isn’t important because it obviously is. For whatever their test material is, the velocities listed are the minimum (or range) at which their projectiles start to deform upon impact. That range will naturally change depending on the material, though, and entering a mouse will differ from an elephant. And, importantly, that velocity range is the easiest thing for the end user to look at when they want to know if a projectile will function as advertised.

tl;dr Saying something doesn’t matter is just a pet peeve of mine because stuff is complex 😜

Did I write that ft-lbs of energy doesn’t matter? Or did I state that’s it’s a useless metric to determine anything about tissue destruction?

Plenty of people/places have tried to model wound ballistics with regards to projectiles, entire conventions and committees have been formed to do just that... and still the most proven way, and the only one that actually shows what to expect in tissue, is to shoot it in tissue and measure the wound.

Look above- the entire hunting and shooting world has little to no idea of what to expect from the projectiles that they are using, and they give up trying to figure it out because they get flood eyed over math equations. Math equations that most sense don’t really hold up.


So, direct question-

I have a 130gr, lead cored, non bonded .264 projectile. Ft-lbs energy at the muzzle is 2,200.

How do I determine whether this bullet will penetrate far enough for use on elk? How do I use that to determine how much damage the bullet will do inside of 100 yards? What about 300? How about 500? What’s the range that the bullet will no longer expand or upset sufficiently to cause rapid incapacitation to a game animal?

As a functional aspect, how does ft-lbs of energy have anything to do with determining whether a bullet is suitable for an animal or shot?
 

Formidilosus

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To clarify, I’m not suggesting that velocity means anything other than it gives a single variable to look at, that when combined with measuring the damage created by projectiles at certain velocities gives ones a very clear indication of what to expect from that bullet in an animal.
 

willfrye027

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I would venture to say, it doesn’t matter. The two bullets you listed are so close, any difference in performance is not going to be repeatable or measurable from a testing standpoint..much less on game in the field.

If you were to change the question to a 215gr HPBT going at 2900 vs a 150gr mono at 3300...it would be more interesting to hear what people think. But again irrelevant if you hit him in the vitals.

“Think” being the operative word here. This stuff is going to be nearly impossible to test in a repeatable, meaningful way. It’s anecdotal at best. Good luck OP, shoot whichever bullet tickles your fancy.
 

Beendare

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Cept in states still not allowing it.
Not allowing what....heavier bullets?

I realize my comment is oversimplified and dumbs it down...but its been a clear difference: a little heavier is better when it comes to the longer shots.

FWIW, all of the kills Ive seen with a rifle are within 400yds.....well within the accepted energy range for each big game cartridge.



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