I'll admit that the OP seems a little big-headed and somewhat condescending. I apologize. I'm not a mean guy, really. I was frustrated at the time I wrote it, three weeks ago, because at the time there were 8 - that's right, 8 - posts on the first page of the board asking about curving bullets. Many of them asserting that it *had* to be possible without any scientific explanation.
With that being said, the OP as well as several comments earlier on this post have already gone into detail explaining why a bullet cannot have a horizontal curve after leaving the barrel *as shown in the movie.* So I'm really not dismissing it quickly. If you can offer an explanation as to how a bullet can curve horizontally *as a result of flicking your wrist* I'd like to hear it. Just make sure you read the whole thread first. Yeah, I know it's long, but we don't want to repeat ourselves.
[quote]I happened to know a few EXPERIENCED gun handlers who think it might be possible to curve a bullet,[/quote]
Yes, and I have had EXPERIENCED "gun handlers" try and tell me that a firearm barrel, if mounted perfectly horizontal to the ground, and fired, the bullet will RISE above the bore several inches before it starts to fall.
Not that the above has anything to do with the myth, just that even "experienced" folks sometimes don't know what they are talking about.
I cannot speak for SchroedingersCat (no offense), but here is a list of experienced gunmen that, when they say something concerning firearms, you can rest assured the source is reliable:
Master Sergeant Army Nurse Boi Former Marine Typ Rick 4070 Black Powder Pulp Lord Frogenhall Bikewer
And so far, I've seen them all saying the same thing about this myth.
The main reason for NOT doing this myth isn't that everyone knows what will happen. They have done myths like that in the past. Some surprised people, while others didn't. The main reason why they shouldn't is because it would be busted in five minutes. They need myths that they can dedicate at least 15-30 minutes to busting on the show. Maybe this would be a good mini-myth for them to do during the commercial breaks, but not something that would be good for an actual show idea. You gotta think about things they can do a show over, not just something you want to see done.
[quote]i had to write this post directed at Mr big shot physicist up there because i'm infuriated at the fact you can so quickly dismiss this myth entirely without giving it an open minded look.[/quote]
We look at everything with an open mind.
[quote]You may have all the experience in physics a text book can throw at you but i bet you have never fired a gun? or even seen one for that matter. [/quote]
In my case, you would lose that bet.
[quote]Just because someone says its not possible doesn't make it true! if that was the case we would still think the earth was flat and think that the atom was the smallest thing known to man. [/quote]
If I only had a dollar for everytime someone tried to use that reasoning as an excuse to test something stupid, I'd be rich.
[quote]I happened to know a few EXPERIENCED gun handlers who think it might be possible to curve a bullet, maybe not to the extreme of the movie but believe its possible. [/quote]
I'll stack my experience against theirs any day of the week. And my knowledge of ballistics as well. They'll probably get an education they will not soon forget.
I've run many tens of thousands of round out of various weapons. But even before I ever handled a real firearm, even as a kid, I could have told you this was nonsense.
While I am astonished that anyone would think there is even a possibility of 'curving' a bullet as shown in the movie, I am much more disturbed by the claim that there are "EXPERIENCED gun handlers who think it might be possible to curve a bullet".
The idea that there are people out there who are handling live weapons and yet have so little understanding of what they can and cannot do is pretty scarey.
[quote]“Hey, Adam, look, the 10 pounder didn’t fall faster. Interesting.”[/quote] Correct me if I'm wrong, but a 10 lb weight and a 5 lb weight do fall at the same speed.
Oh, and another thing. If you remember correctly the Mythbusters have done Hollywood myths before. and the thing to test for this one, would not be if a bullet can curve, but what can they do to make it curve. Isn't that what the mythbusters are about?
[quote]and the thing to test for this one, would not be if a bullet can curve, but what can they do to make it curve. Isn't that what the mythbusters are about?[/quote]
Well, the message I was trying to get across in the OP is that the concept of curving a projectile horizontally by flicking your wrist is a violation of extremely basic physics. So basic that it's along the same lines as asking if two different weights fall at the same speed. Newton's laws of motion really are among the first things you learn in a physics class. It doesn't get much more basic.
Yes, they've tested movie myths before, but there were usually a lot of variables involved. In this case there is just one: the absence of a horizontal force. As mentioned before, this would just be too easy to bust. It would probably make a good mini-myth, but that's all. I would hope that the show does not run out of ideas and has to test if basic scientific laws are valid. I don't think that's what Mythbusters are about. I wouldn't want to watch an episode where they drop different weights and see how fast they fall, test if water really does freeze at 0 C, check if PV=nRT, etc. I was already dissapointed when they tested pyramid power.
[quote]It has also been commented on that this piece of movie BS (I refuse to call it a myth), has to do with modern bullets as seen in the movie "Wanted", nothing more and nothing less.[/quote]
Well, yes, the movie scenes are a load of bovine excrement, but the question was "can it be done?" So let's take bits from the preview and see...
Assume a typical 9mm FMJ bullet, looks like 115 or 124 grains, with engraving on the sides (and yes, that does make a difference). If fired from a gun moving horizontally at a sufficient velocity, the bullet WILL curve due to a force other than gravity. Here's how:
Let's assume a right handed twist to the rifling, and a right to left movement of the barrel during firing.
When you add the forward and sideways vectors of the bullet, it will be moving through the air with a sight degree of yaw, allowing air to pass over the bullet from left to right. Due to the spin of the bullet, the air passing over the top of the bullet will encounter less friction than the air passing over the bottom of the bullet (the Magnus effect), resulting in a net force upwards. The engraving, just like the stitches on a baseball or dimples in a golf ball, will magnify this effect. To curve the bullet sideways, you just need to do the same thing, only with a vertical movement; up for left, down for right.
Now admittedly this is a tiny, tiny vector, but given enough time of flight, it can have an effect. Ever looked at the ladder sight in a Springfield 1873 rifle? Flip it up, and you'll see it's slightly canted to the left. This is because out at ranges of 2,000 yards, the range the rifle sights were calibrated to, the right hand twist of the bullet causes it to drift significantly to the right, therefore you must aim to the left of the target to hit it. And even at 2000 yards, taht's short range; the .45-70-405 was replaced by the .45-70-500 cartridge in some applications because testing at Sandy Hook showed the heavier bullet had an effective volley range of 3,500 yards--that's two miles! For verification of the angled sights on rifles, see the 1911 Encyclopedia Britannica entry on "Ordnance", for verification of the .45-70-500 range, see the 1879 Sandy Hook tests.
And yet an angled path, whether from wind or any velocity vectors, is just that, an angled path not a curved path. Even if it hits to the right of where you "thought" you were aiming, it still follows a straight-line path to the point of impact -- it will still not curve behind an obstacle.
i agree 100% with you bro, but you forgot one thing, the recoil, they used .45, with kicks really hard, most people who use .45 rounds pistols use both hands to fire, to keep a steady had and resight the target, now if you fire a .45 with one hand and swing your gun like that in the movie, your risk is gonna be messed up pretty bad. for those who dont know much about guns, standard police pistols are 9mm witch is small, but not as samall as .22 with cant kill anything from past 250 yards, 9mm are ideal weight and size to put the target on the groud, .45s would just kill the target before they hit the ground(depending where the target is hit) .45 puts a huge hole in a human, depending on witch type of a round you use, theres: High Velocity(cuts the air faster to travel at higher speeds) Hollow Point(puts a huge hole when exiting target).
to sum it up, NO! swinging a .45 M1911 like that would break your risk.
[quote]And yet an angled path, whether from wind or any velocity vectors, is just that, an angled path not a curved path.[/quote]
Yes, but you're making an invalid assumption. Fire a bullet in a 30 fps crosswind, and the bullet doesn't instantly gain a 30 fps sideways velocity, it has to accelerate up to that, which takes time. Acceleration gives you a curved path. Same thing for curveballs, airsoft hop-up, and .45-70 bullets dropping down towards a target at 2000 yards. Those all result in a force that accelerates the projectile, and until the acceleration drops to zero (i.e. the wind accelerates the bullet to 30 fps sideways), the path will be curved.
[quote]Fire a bullet in a 30 fps crosswind, and the bullet doesn't instantly gain a 30 fps sideways velocity[/quote]
Referenced to the ground, yes it does (other than a minor lag). It continues at it's 1000 fps or whatever, through the moving air, which moves it at a constant speed sideways.
[quote][quote]Fire a bullet in a 30 fps crosswind, and the bullet doesn't instantly gain a 30 fps sideways velocity[/quote]
Referenced to the ground, yes it does (other than a minor lag). It continues at it's 1000 fps or whatever, through the moving air, which moves it at a constant speed sideways.[/quote]
Well, let's do the math and see. Assume a 124 grain, 9mm bullet. The side surface area of said bullet will be roughly the same as a rectangle of 9mm by, say, 15mm, so that's 1.35cm^2. 124 grains is 8 grams. A mole of air at STP masses about 28.8 grams and occupies a volume of 22400 cm^3. A 30 fps wind is about 900 cm/s. That means that with 0 lateral velocity, the bullet must stop a column of air of 900 * 1.35 = 1,215 cm^3, which is 0.05 grams. To "accelerate" that mass of air to 900 cm/s in one second is going to require an average acceleration of 900 cm/s^2 , so the force required is 0.05 g * 900 cm/s^2. or 45 g cm/s^2.
Now, apply that same force back on the bullet, and see how fast it's going to accelerate. 45 g cm/s^2 = 8 g * a, so the acceleration on the bullet would be 5.6 cm/s^2. Now, as the bullet approaches windspeed, the force is going to drop off to zero, but let's just use it as a constant right now so I don't have to do any calculus. 900 cm/s = 5.6 cm/s^2 * t, which gives us a t of 160 seconds for the bullet, under constant acceleration, to reach a velocity of 900 cm/s. The real answer is going to be much, much larger than that, since the acceleration is going to be continuously decreasing.
[quote]Fire a bullet in a 30 fps crosswind, and the bullet doesn't instantly gain a 30 fps sideways velocity, it has to accelerate up to that, which takes time.[/quote]
Not long. Punch it up in any decent ballistics calculator.
The drift to the side due to rifling is very small, and while there is a very slight curve to it, it is best described as an angle.
