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Old July 18, 2013, 11:40 PM   #1
engineglue
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Weight - Energy Ratio Chart

I've started putting together a comparison chart which shows the weight-energy ratio between various rounds and a 22lr. I did it this way because the amount of force inflicted on tissue is related to the weight and energy of the bullet, not just energy. I've also included the test barrel size so you can compare the cartridges to pistols you may own.

It's interesting to see that some 45 acp rounds are more powerful than some 10mm rounds. It's also unfortunate to see how low in power the 22 wmr is and the 500 s&w is insane!

http://cartridges.intinex.com/

For reference, you can see that the Blazer 115G 9mm fired from a 4" barrel is about 10 times as destructive than a CCI Mini Mag 22lr fired from a Ruger SR22.

Let me know if you want to add more cartridge brands and/or models.
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Old July 19, 2013, 03:21 AM   #2
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'Splain this whole "Weight-Energy Ratio " thing a little more please.

I can see that ft-lb of kenetic energy is starting point. Are we then factoring the weight of the bullet , or the weight of the gun ?

And what was it that this " Weight-Energy Ratio " supposed to measure / help us to understand ?
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Old July 19, 2013, 09:02 AM   #3
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Momentum (product of mass x velocity) is a more valid measure for comparison. But energy yields a larger figure and is much sexier for marketing purposes. So, that's what manufacturers publish.
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Old July 19, 2013, 02:37 PM   #4
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Quote:
For reference, you can see that the Blazer 115G 9mm fired from a 4" barrel is about 10 times as destructive than a CCI Mini Mag 22lr fired from a Ruger SR22.
Really?

That's quite a claim indeed- one that I doubt anyone could prove with any degree of certainty, even with the information provided in the chart in the link.
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Old July 19, 2013, 10:42 PM   #5
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Why is everything compared, or rated to the .22 l.r.?

A lot of work has gone into this chart. What does it illustrate?

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Old July 21, 2013, 01:55 AM   #6
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Imagine how much energy it would take to push a needle through ballistics gelatin. It wouldn't take much, right? How much damage would it cause? Not much.

One formula I wanted to use is; penetration equals bullet weight times velocity divided by the diameter of the nose of the bullet divided by five. I don't really have the resources to acquire the data needed to make a chart which utilizes this formula.

The formula in the chart is; (the energy of the cartridge times it's bullet weight) divided by the energy of a 22lr divided by the bullet weight of a 22lr.

I'm attempting to chart a somewhat accurate comparison of penetration or damage for different cartridges from different firearms.

If you have a better formula, let me know. This data is in a database and I can easily add or delete records. I can also change the formula.

If I had the resources, I would purchase many types of cartridges and firearms, fire them into a custom made sternum simulate with gelatin backing, measure the velocity, the mass of the bullet, the weight of the bullet, the diameter of the nose of the bullet, the total diameter, and the expanded diameter for hollow points, penetration distance, and wound cavity. Now, wouldn't that be one hell of a chart?

I would then use that data to create a formula for calculating penetration and wound volume based on the velocity, diameter and mass of the projectile.

Some physicist probably already knows this formula. If I knew the formula, I could just make the chart but I don't know any physicists.
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Old July 21, 2013, 09:52 AM   #7
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I don't understand your chart at all. The final number does not appear to compare the bullet weight to the muzzle energy, unless you are using a formula that raises at least one of the factors to some exponential factor.
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Old July 21, 2013, 10:15 AM   #8
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Interesting. Looks like eventually you want to develop
comparisons based on actual tissue damage criteria?

Been quite a few people down that path already. Seems
like every few years someone takes a run at it, usually
generating results that conflict somewhat with previous
research.

Have you searched "Marshall and Sanow" and "Strasbourg
Goat tests"??
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Old July 28, 2013, 12:33 PM   #9
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Quote:
Originally Posted by engineglue:
One formula I wanted to use is; penetration equals bullet weight times velocity divided by the diameter of the nose of the bullet divided by five. I don't really have the resources to acquire the data needed to make a chart which utilizes this formula.
The formula you propose sounds an awful lot like Vernal Smith's equation for bullet penetration in wetpack- basically momentum divided by velocity and a scaling factor....

Penetration (inches) = Bullet Weight (lbs) x Impact Velocity (fps) / Meplat Diameter (inches) / 5

...found here http://www.rathcoombe.net/sci-tech/b...s/methods.html

It's not bad for being as simple as it is- linear equations have a certain robustness that seems to compliment their simplicity.
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Old July 28, 2013, 05:30 PM   #10
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Quote:
Originally Posted by engineglue
I've started putting together a comparison chart which shows the weight-energy ratio between various rounds and a 22lr...
And so what does this really tell us and how can we make practical use of the information?

Quote:
Originally Posted by engineglue
...I did it this way because the amount of force inflicted on tissue is related to the weight and energy of the bullet, not just energy....
So what?

Quote:
Originally Posted by engineglue
...For reference, you can see that the Blazer 115G 9mm fired from a 4" barrel is about 10 times as destructive than a CCI Mini Mag 22lr fired from a Ruger SR22...
No I can not see that because your chart doesn't say anything of the sort.

On your chart the weight energy ratio of a Blazer 9mm 115 grain to be 10.55 times that of the .22. But that doesn't tell us anything about how destructive each bullet is. You are apparently merely assuming that the weight energy ratio correlates in a positive, and linear, fashion to tissue destruction.

So before you start tossing around claims about the comparative destructiveness of various cartridges you need to establish the validity of your threshold assumption.
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Old July 29, 2013, 10:21 AM   #11
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That's a whopping lot of work that you put into this.
And it's most interesting, as an addition to our general knowledge of the subject.
Can't ever know too much.
Thanks for sharing.
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Old August 3, 2013, 10:04 PM   #12
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I always used (weight x velocity x Diameter)/7000(grains per lb) to get my bullet power ratings. its not perfect but it does give me a good comparison, think it was in a "cartridges of the world" book but i cent remember for sure.
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Old August 4, 2013, 08:03 AM   #13
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I believe you should add a couple of reference points into your table.

My Suburban weighs 4,000 pounds (2,800,000 grains). Moving at 1 inch per second (.083 FPS) it has .42 ft-lb of energy.

Using your formula, this gives a "weight energy ratio" of 3,341.

This means that according to you, getting hit by my Suburban at 1 inch per second is 3,341 times more destructive than a .22, and over 10 times more destructive than a .500 S&W Magnum!

I'll have to try it, but I doubt if I'll even notice getting hit by my Suburban at 1 inch per second. On the other hand, I have no intention of being hit by a .22 or a .500 S&W!

I'm an even better example. I weigh 160 pounds (1,120,000 grains) and walk at about 2 MPH (3 FPS). This means that while walking I have 22.3 ft-lb of energy, with a "weight energy ratio" of 7,127! Wow!

Me walking into you means that I'm over 7,000 times more destructive than a .22, and 20 times more destructive than a .500 S&W Magnum! I'm like a super-hero!

Last edited by 45_auto; August 4, 2013 at 09:11 AM.
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Old August 4, 2013, 09:05 AM   #14
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Old August 4, 2013, 09:19 AM   #15
45_auto
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More like "no meaningless jumble of numbers goes unpunished". Force, energy, mass, velocity, and acceleration actually mean something in the real world.

The OP needs to take a few physics classes.

Quote:
I did it this way because the amount of force inflicted on tissue is related to the weight and energy of the bullet
Actually force = mass x acceleration and has nothing to do with energy.

Kinetic Energy = mass x velocity squared / 2.

Multiplying KE by mass again like the OP is doing gives you mass squared x velocity squared / 2. Then taking the ratio of that meaningless number to the meaningless number generated by a .22?

Why would anyone think that squaring the mass of the projectile means anything? It just makes the velocity and therefore energy much less significant (per my Suburban and person example 2 posts above).

Not denying that it was obviously a good bit of work, but it means nothing. Unless the OP has some research showing his numbers actually mean something, he might as well take the wavelength of the color of the brass times the weight of the gun firing the cartridge squared and chart those numbers. They'll mean just as much and be just as relevant.

Last edited by 45_auto; August 4, 2013 at 09:29 AM.
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Old August 4, 2013, 09:56 AM   #16
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Put things in context:

I put you up against a wall where you can't move.
I allow that 4,000-lb Suburban to impact you doing 1 ft/sec
I submit the area of your gut so impacted is tantamount to mush approx 1 sec later.

It's all in how you set up the problem.

Now........ I'll admit that terminal ballistics/performance is incredibly complex, and greatly dependent
not only on bullet speed/diameter/weight, but also on bullet metplat (at BP and/or non-exotic
handgun speeds), sectional density, jacket design (high speeds), target characteristics (skin
types/flesh/organ densities/voids, bones/thicknesses, impact angles, intervening
glass/metal/wood barriers, etc, etc, etc

But energy does finally matter -- within those contexts

Last edited by mehavey; August 4, 2013 at 10:06 AM.
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Old August 4, 2013, 10:35 AM   #17
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Quote:
Originally Posted by mehavey
I put you up against a wall where you can't move.
But that has nothing to do with the OP's claims. It demonstrates entirely different principles.
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Old August 4, 2013, 10:49 AM   #18
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Quote:
Originally Posted by 45_auto
Me walking into you means that I'm over 7,000 times more destructive than a .22, and 20 times more destructive than a .500 S&W Magnum! I'm like a super-hero!
You are one mean SOB!
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Old August 4, 2013, 11:06 AM   #19
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A while back I created a spreadsheet to compare energy values of different calibers I am interested in at different distances starting from the muzzle. I posted a thread regarding that was met with mixed reception here but someone shared a link to brassfetcher.coms website comparing different calibers penetration value in ballistic gelatin. Pretty much summed it up for me, let them do all the work that spreadsheet data entry got boring anyways.

I ended up taking the averages of all the muzzle energy data I had collected into one chart though, I still refer to the number for each caliber as a reference for buying ammo, sort of a benchmark. I suspect something similar to that is what the OP is looking for in his study, a way to compare and quantify performance of a caliber perhaps.

Im not qualified to say if its accurate but the OP's chart would be easier to read if it was filtered by caliber instead of ratio... id be more interested in comparing the ratios of all the selections within the caliber to each other than comparing the ratios of all calibers out there is not useful to me.
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Old August 4, 2013, 01:44 PM   #20
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Quote:
I always used (weight x velocity x Diameter)/7000(grains per lb) to get my bullet power ratings. its not perfect but it does give me a good comparison, think it was in a "cartridges of the world" book but i cent remember for sure.
I believe that's what's known as the Taylor Knock Out Value or just Taylor KO. Developed by John "Pondoro" Taylor, best known for his big game hunting/poaching in Africa.

Obviously it favors large bore cartridges.

Interestingly (to me anyway), Hornady has a sort of cartridge effectiveness calculator that tends to favor just the opposite. It's called Hornady Index of Terminal Standards (H.I.T.S). Sounds fancy, but it's just a sectional density*momentum relationship ...specifically, it's (mass*mass*velocity)/(diameter*diameter*700000).

Where as the Taylor KO value probably is intended to predict wound channel width and rate of energy dump, the H.I.T.S. value seems to be more an indicator of penetration. Of course, neither can quantify bullet materials/design, which can end up making a lot of numbers pointless.

Last edited by idek; August 4, 2013 at 03:36 PM.
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Old August 4, 2013, 02:41 PM   #21
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Quote:
Quote:
Quote:
Originally Posted by mehavey
I put you up against a wall where you can't move.
But that has nothing to do with the OP's claims. It demonstrates entirely different principles.
Actually not as much as it might appear, as the human/male body at 180# really doesn't move as a high speed bullet drives in. Therefore the bullet energy is expended/damage is done internally.

The lack of Suburban "damage" from a 1 ft/sec impact comes from assuming that the human body simply moves as a unit backwards at a similar speed -- with little damage (if any) done at all.

But stop that gross body movement, and the Suburban's energy -- small as it might seem -- is expended in crushing the body's internal organs.

The examples are nor so far off as they seem.
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Old August 4, 2013, 03:21 PM   #22
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Quote:
mehavey posted:
Actually not as much as it might appear, as the human/male body at 180# really doesn't move as a high speed bullet drives in. Therefore the bullet energy is expended/damage is done internally.

The lack of Suburban "damage" from a 1 ft/sec impact comes from assuming that the human body simply moves as a unit backwards at a similar speed -- with little damage (if any) done at all.

But stop that gross body movement, and the Suburban's energy -- small as it might seem -- is expended in crushing the body's internal organs.

The examples are nor so far off as they seem.
There's no way in the world that a Suburban hitting you with your back against the wall while it's only travelling one inch per second (not one foot per second, 45 Auto calculated it at one inch per second; that's extremely slow, that's just over one twentieth of a mile per hour) will do more than ten times the damage of a 500 S&W Magnum and 3,341 times the damage of a .22 LR. I'd be surprised if you had any more than some bruising and maybe some cracked ribs from the Suburban hitting you while going that slowly, even if your back was against a concrete wall.

No, it's pretty clear the OP's chart is extremely flawed and doesn't really represent any real-world values.
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Old August 4, 2013, 05:32 PM   #23
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Sorry. I'd read it as 1 ft/sec
My bad.
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