January 25, 2017, 11:28 PM | #1 |
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The energy gimmick
Most boxes of ammo now include not just trajectory data, but kinetic energy as well. The idea is that energy is a measure of killing power, but it isn't. A baseball has more energy than a small caliber handgun, and a football player at a dead run has more than a 357 magnum! Most of us wouldn't want to be hit by either a football player or a baseball, but neither would be fatal. Consider also that a FMJ bullet has the same kinetic energy as a hollow point, but the hollow point does much more damage. There are plenty of formulas that try to quantify stopping power, but the only real way to measure it is empirically. Tissue damage to vital organs, not kinetic energy, is what kills.
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January 26, 2017, 12:36 AM | #2 |
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Energy isn't a gimmick, it's a formula, E=mv^2
I think manufacturers put it on the boxes because it's one of the only things to go on as far as performance. There isn't a lot of real life practical data to reference besides ballistic gelatin tests, and as far as actual people go, the human body is so varied that the way one bullet preformed in situation A is not going to necessarily exhibit the same results in situation B.
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January 26, 2017, 12:57 AM | #3 | |
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January 26, 2017, 01:01 AM | #4 |
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it would be awesome if manufacturers put ballistic gelatin results on their boxes. But until then energy isn't irrelevant.... All other things equal Id rather buy the one with more energy, and I'm certainly not buying anything that doesn't list it at all.
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January 26, 2017, 02:41 AM | #5 | ||
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back in the "stone age" ammo makers didn't put any velocity, trajectory, or energy information on the box. Caliber and bullet weight and usually bullet type was it. (along with the boilerplate "use only in..." type info). To find out velocity, trajectory and energy, one had to go to a printed table (websites were where spiders caught their food), in the maker's catalogue, or in books such as Shooter's Bible or Gun Digest, or in reloading manuals. Quote:
It's for comparison between rounds, a general, not an specific accurate performance predictor. Like ballistic gelatin, it gives us a uniform standard for comparison of potential, not actual results. Energy is a straight mathematical computation, and does not address ANY of the other factors that determine how effective a given round will be.
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January 26, 2017, 04:59 AM | #6 |
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Kinetic energy is proportionate to the square of velocity, while it is only directly proportionate to mass.
So, small changes in velocity make a big difference in the amount of energy. Much bigger than changing the weight. So, it's possible to end up with outrageous amounts of energy by firing a a lightweight (for caliber) projectile at a relatively high velocity. Large amounts of energy make for impressive advertisements. The problem is that such bullets tend to disintegrate and offer very poor penetration. Energy isn't the whole story. Because of this, I would even regard a statement of energy as a point of suspicion, and especially if it's used as a primary selling point. If I were going to pin a number on stopping ability, I think momentum is generally more relevant. The problem is that a chart of similar numbers makes for unintertesting advertisements. |
January 26, 2017, 07:53 AM | #7 | |
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January 26, 2017, 08:51 AM | #8 | |
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No, energy is not a gimmick. It is simply information. How it is used is a whole other matter. If YOU don't like the information, then don't use it.
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January 26, 2017, 09:05 AM | #9 |
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As long as you are comparing bullets of similar size, weight and construction energy numbers are a pretty accurate way to predict effectiveness. There is nothing wrong with providing the data, but the user must be able to correctly interpret the data.
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January 26, 2017, 09:09 AM | #10 |
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Knowing barrel length of the test data would be helpful.
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January 26, 2017, 10:20 AM | #11 |
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I prefer to think about kinetic energy figures like the horsepower rating of a car; it's not very helpful without also knowing and understanding a bunch of other information. 240 hp in a Lotus Exige means a very different thing than 240 hp in a Ford F-350.
They're also comparable in that anyone who claims that it's the only important number is probably naive and/or completely obsessed with only one aspect of its performance.
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January 26, 2017, 10:38 AM | #12 |
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I'm pretty sure SAAMI lists desired test barrel lengths by caliber... but for rifles, the most common is see is 24".
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January 26, 2017, 11:13 AM | #13 |
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Sounds like the ammo manufacturers have borrowed from the auto makers advertising department.
Horsepower sells cars, energy sells ammo. Neither one tells the whole story, though.
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January 26, 2017, 11:20 AM | #14 |
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Not a gimmick, not the whole story either.
The OP is more gimmicky than what it complains about if facts still matter. They can't put it all on the box. Those that do are attempting to provide a bit of information to their customers. Is it marketing? It is useful? Yes to both. The gun industry, and the consumers thereof, really need to do less shaming, less complaining, and more getting new shooters to the range, teaching the skills of hunting, marksmanship, etc. |
January 26, 2017, 12:57 PM | #15 | |
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Nowadays, there are so many gimmik load options it wouldnt surprise me to find some 9mm HP with only 200ft lbs... If you dont get the results you expected, you have to question the load you bought before you consider trading the gun. These days, If it doesnt list the velocity and energy on the box its a scam. I think adding ballistic gel data on the box is a good idea actually.
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January 26, 2017, 01:09 PM | #16 | |||
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January 26, 2017, 01:27 PM | #17 |
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"...the hollow point does much more damage..." Yep. Because it gets bigger in diameter upon impact with the same amount of energy.
A football player at a dead run isn't anywhere near as fast as any bullet. "...Tissue damage to vital organs, not kinetic energy, is what kills..." Nope. Bullets kill with energy not blood loss or tissue damage. Really the shock that comes from both. Anyway, the energy they're talking about is the mathematical acquired potential/kinetic energy of a given bullet weight at a given speed. Not a gimmick. It's physics. And there's no such thing as 'stopping power'. No cartridge, rifle or handgun, will give a 100% guaranteed one shot stop. Physics doesn't allow it. "...Horsepower sells cars..." To men. Colour sells 'em to women. snicker.
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January 26, 2017, 02:47 PM | #18 |
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Kinetic energy numbers have been included in hunting regulations in in various states in the US, and in Africa, and Europe. And in ammunition specifications provided by military and law enforcement agencies all over the world, and by the companies that make that ammunition. And in specifications from manufacturers and buyers of other military weapons, such as mines. And in specifications written up by manufacturers and buyers of bullet resistant products.
A lot of people must find the concept useful. |
January 26, 2017, 06:40 PM | #19 |
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Regardless of one's personal view about the usefulness of the information, energy numbers are included on a lot of ammunition simply as a point of comparison.
It's like 0-60 mph times for econo cars and light trucks .... not very useful, but a point of comparison between models. And for some cartridges, the energy number(s) are included because the cartridge meets some magic number that has been adopted as a requirement for a specific application. .327 Federal Magnum, for example, listed energy figures on the ammunition when it was released, because the American Eagle 100 gr soft point load met the 500 ft-lb energy requirement for hunting big game in certain states; and the other loads included the information to show that they came up shy (and were illegal in those states).
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January 26, 2017, 09:24 PM | #20 |
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I love the energy v. momentum discussion every time it comes up in this forum. If you place equal energy into a lightweight bullet versus a heavy one, the light one will travel faster, arrive quicker, and with greater velocity. Both retain equal energy, minus that lost in transit to friction. Energy quickly transferred is energy quickly lost. Energy becomes heat as the bullet deforms itself as well as the struck object. An object with greater mass (which is conserved), retains the energy and transfers it more slowly.
The human on earth has tremendous mass and a fall from standing produces enough potential to kinetic energy to crack most skulls wide open. The sun has tremendous energy, and radiation, although absorbed as molecular electric / heat / kinetic energy in the skin and organs, hardly makes us bleed. The key is in the proper proportion, delivered at the appropriate rate. One cannot with equal energy split wood with a fast machete, or a slow sledge, but only a sharp axe.
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January 26, 2017, 11:56 PM | #21 | ||
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In light of that, putting that number on the ammo box makes good sense, providing a handy "in the field" reference that shows your ammo meets the requirement. (or doesn't).
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January 27, 2017, 12:35 AM | #22 |
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I haven't seen any states hunting ammo energy requirement that wasn't flawed. Obviously many wildlife officials are not that familiar with guns. In my state you can legally hunt deer with a .25acp. Thank god even the craziest of yahoos are smarter than that but I'm sure the wildlife official has a degree in something...
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January 27, 2017, 10:00 AM | #23 | |
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If you are talking about the eggheads that actually write the law, I would agree with you. They probably know virtually nothing about firearms and the low K/E requirement is based off of ensuring that bow hunting will be allowed. As we know, K/E of a arrow and K/E of a bullet are apples to oranges. |
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January 27, 2017, 10:35 AM | #24 |
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Energy if fun to play with but is not the end-all when it comes to hunting bullets.
I attended the Northwestern Traffic Institute on Traffic Accident Reconstruction. We played with the numbers where if you got a bumble bee going fast enough it would exceed the energy of a freight train (eng. only) and it theory would stop a freight train. But we know math alone will not stop a freight train, no matter how fast you can get a bubble bee to fly. A more realistic example it comparing two bullets of the same weight at the same velocity. Lets say, a 150 FMJ 30 cal bullet going 2700 fps, with a 150 gr. Soft point 30 cal bullet going 2700 fps. Both are going to have the same KE, about 2430 ft lbs. (2428.7 to be exact). Which of the two would make the better hunting bullet. One more then likely will pass through, expending its energy in the air until it hits the ground someplace down range. The other is more then likely going to expand and expend its energy in the critter. But like I said, its fun to play with the numbers. Not as much fun now as it use to be when we had to use a slide rule, but still fun. As I have said in the past, "sniping isn't about the gun/ammo, its about the weaponization of math".
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January 27, 2017, 03:14 PM | #25 |
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If you could get that bumble bee going fast enough, it would turn to plasma, which could burn a hole through that train engine, lengthwise...or so the math says..
Our thinking about "what" does "what" when it comes to bullet performance in a target medium is somewhat channeled by the terms and math we use to describe it. Kinetic energy is energy of motion, energy doing work, and a bullet has that as long as it is moving, but, that is all just potential until it strikes the target. Target resistance forces some of that energy to work on the bullet, itself, which is why a hollow point expands. You could say that the energy used to expand the bullet is "lost" because it doesn't directly affect the target, and be mathematically correct. However, like energy lost when the bullet exits, it doesn't matter. All that matters is that there is enough energy to drive the bullet where it needs to go to get the job done, under all possible conditions. If you have enough to do that, where any excess goes is a moot point.
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