What is Gun: Definition and 311 Discussions

A gun is a ranged weapon designed to use a shooting tube (gun barrel) to launch typically solid projectiles, but can also project pressurized liquid (e.g. water guns/cannons, spray guns for painting or pressure washing, projected water disruptors, and technically also flamethrowers), gas (e.g. light-gas gun) or even charged particles (e.g. plasma gun). Solid projectiles may be free-flying (as with bullets and artillery shells) or tethered (as with Taser guns, spearguns and harpoon guns). A large-caliber gun is also referred to as a cannon.
The means of projectile propulsion vary according to designs, but are traditionally effected pneumatically by a high gas pressure contained within the barrel tube, produced either through the rapid exothermic combustion of propellants (as with firearms), or by mechanical compression (as with air guns). The high-pressure gas is introduced behind the projectile, pushing and accelerating it down the length of the tube, imparting sufficient launch velocity to sustain its further travel towards the target once the propelling gas ceases acting upon it after it exits the muzzle. Alternatively, new-concept linear motor weapons may employ an electromagnetic field to achieve acceleration, in which case the barrel may be substituted by guide rails (as in railguns) or wrapped with magnetic coils (as in coilguns).
The first devices identified as guns appeared in China from around CE 1000. By the 12th century, the technology was spreading through the rest of Asia, and into Europe by the 13th century.

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  1. S

    Rail Gun Propulsion: Perverting a Rail Gun Into a Rocket?

    Is it possible to pervert a rail gun into a rocket? I'm understanding that plasma conducts electricity. If i could supply a rail gun with constant current and send in a constant feed of hot plasma into the rail gun would the machine send out plasma at high enough speeds to be used as a rocket...
  2. S

    Why is exit wound in a rifle gun shot injury bigger than entry wound?

    Hi, Generally if u see a post mortem skull after a rifle shot injury, exit wound is bigger than entry wound. Shouldn't the bullet lose lots of its energy when coming out, hence smaller wound. Maybe it is spinning or something, but I want to get others views. Thanks :smile:
  3. Greg Bernhardt

    News Senate kills gun control background check amendment

    Senate rejects background check amendment 54-46 http://www.cnn.com/2013/04/17/politics/senate-guns-vote/index.html?hpt=hp_c2 I'm having difficulty finding the actual bill. Does anyone have a link? I'm sick of reading summaries and opinions without reading the actual bill. I tried searching...
  4. F

    Spring powered dart gun conceptual question

    1. Problem statement. A spring powered dart gun fires darts straight downward towards the Earth from the same height each time. First it fired a regular dart, then a dart with twice the mass. Which dart takes the least time to reach the ground after exiting the gun? A) the regular dart B) the...
  5. tsuwal

    What are toy gun caps made of?(those red circls that make a lot sound)

    http://wildwesttoys.com/db1/00001/wildwesttoys.com/_uimages/capsforwebsite2.JPG Do they have gunpowder?
  6. mrspeedybob

    Why is the rail gun an interesting weapon?

    This video is from 2007 but it stated the goal at that time was a 64 mega-joule weapon? I understand the advantages of extended range but it seems like a huge, awkward, and expensive weapon to deliver a relatively small amount of energy. 64 mega-joules is the equivalent of only 14 kg of TNT...
  7. A

    News The ATF and their role in gun control

    The NRA says it wants existing laws to govern the control of firearms. The NRA removed the power of the ATF to execute the existing laws. My forecast for future political action is that the NRA will face full legal disclosure in the SCOTUS. Todd Tiart - Fox news July 19 2011 Todd Tiart...
  8. J

    What is the smoking gun that validates ADS/CFT

    To my understanding there is no proof of ADS/CFT but people seem to take it as absolute fact. What is the reason for this?
  9. genxium

    Can I make an electron gun at home?

    I'm quite interested in home-made devices, last year I tried making a sinusoidal wave oscillator at home and succeeded. It feels good to DIY some coarse devices, and recently I'm learning to build a Cathode Ray Tube. However, it's not going successful with me; I would like to build an electron...
  10. S

    Buy High Voltage Electron Guns Up to 40kV - Expert Advice

    Hi folks, In need of some advice. Can anyone recommend any companies selling high voltage electron guns up to 40kV? Thanks!
  11. M

    News Should assault weapons be banned to reduce gang violence?

    Irrelevant. You missed what I was referring towards. You don't need a shotgun to hunt an animal that is practically unaware or really doesn't care about your presence around it. This is just an opinion, so there is really no argument to be had here. I really don't care what makes a great...
  12. T

    Up/down electron gun construction?

    up/down electron gun construction?? Greetings! I'm working on a project that Requires a roughly equal number of up and down spin electrons to be injected into a (vacuum or ATP) chamber. Is there a common device that does this? If not, would it be possible to build one and how would it work...
  13. B

    News Public opinion regarding US Gun laws.

    About a month ago 2 police officers were killed in a "Gun and grenade attack" in Greater Manchester, UK: http://www.telegraph.co.uk/news/uknews/crime/9550417/Two-female-police-officers-shot-dead-in-Manchester-as-man-arrested.html This lead to the inevitable re birth of the topic "Should we...
  14. A

    What is the final speed of the cork in a spring loaded cork gun?

    Homework Statement A cork gun contains a spring whose spring constant is 20.0 N/m. The spring is compressed by a distance ∆X = 8.2 cm and used to propel a cork of mass 3.76 g from the gun. Assuming the cork is released when the spring passes through its equilibrium position (Xeq). (a) What...
  15. J

    Projectile motion boat gun problem

    Homework Statement A speedy destroyer’s 5 inch gun fires a projectile at some angle to the horizontal. If the thing travels a distance of 23 500 m in 135 s, what was the projectile’s initial velocity? Homework Equations v=vi+at v^2=vi^2+2a(s) s=displacement s=vi*t+.5at^2 The...
  16. S

    Combustion potato gun - Need associated variables, ideas and concepts.

    Hi Guys, I have a Year 11 Project weighted 15% of my year mark due in 5 weeks. For my project I've decided to build a classic combustion potato gun. This gun will consist of pvc piping, barrel, Lantern lighter, any other components and of course hairspray (combustion) Anyways It is still only...
  17. S

    At what height should a gun be fired for bullet to have escape velocity

    Hello, can you can tell me if this is correct? I thought the height would turn out close to where satellites orbit, but it comes out to about 5.5 million miles away! I was very surprised by this, that's about 20 times further than the moon. Here's what I used Escape velocity: Ve = sqrt(2GM/r)...
  18. N

    The Devil's Gun: What Point Achieves Max Acceleration?

    A question for you learned gentlemen and ladies: The Devil being a crafty sort of fellow and not caring one nit about gun control laws decides to create a gun of infinite barrel length, loaded with a bullet containing an infinite charge of gunpowder/blackpowder or the like. Presuming his...
  19. I

    What Voltages Should Be Used for Focus and Deflection Plates in an Electron Gun?

    Hi all, I am making electron gun. I have several High voltage power supply to provide enough voltages to Filament, Anode, Grid, Focus and deflection plates. I want to make electron gun of acclerationg potential of 5-8 KeV. I know I have to give negative supply to cathode or filament. and then...
  20. J

    Is it safe for a 15-year-old to build an electron gun with dangerous elements?

    Im 15 from the U.K and i want to do something with my life. So i jumped to the conclusion of building something, i didnt want something like a cyclotron, but i wanted to start of with something easier such as a electron my goal is to try and build an electron gun. I want to try and make this...
  21. A

    Does a sling or a gun exert more initial force of the projectile?

    First of all this is probably the only time I will be on this forum. At first this seems a no brainer. But I am a weekend survivalist and I made a sling that can sling rock a little more then 1" in diameter 120 yards at an angle of about 50-55 degrees. After some research the type of rock I...
  22. Greg Bernhardt

    Fake Gun Used to Steal Man?s Virtual Currency

    Two men recently met in the Fordham University library for a simple currency exchange: $3,300 for 4.7 billion RuneScape coins. *When the deal looked shady, the seller of the coins wanted to back out. *That’s when the alleged buyer pulled … Continue reading...
  23. rootX

    News What has the US done to tackle gun shootings?

    As a non-local, I have no clue what is been done in the US to prevent shootings from reoccurring. What keeps on happening in the US, most people up here call it insanity. The shooting news catch international attention yet prevention measures and actions from the governments don't come in the...
  24. J

    How Does a Rail Gun Work Without an External Magnetic Field?

    http://www.brightstorm.com/science/physics/magnetism/faradays-law-lenzs-law/# Start at about 7:10 and watch until about 8:20. I can see that an emf and hence a current will be induced in the rod between the two rails BUT if there is no external magnetic field (the magnetic field generated by...
  25. D

    Electron or Proton gun (+/- charge) from magnetic field?

    Homework Statement The news just announced that aliens armed with either electron- or proton-guns have invaded the city. A quick glance reveals that there is indeed an alien on the street just below my top-floor, north-facing window. When the alien shoots his rifle vertically at the sky, the...
  26. L

    How Does the Doppler Effect Alter Radar Frequencies?

    Homework Statement Radar is used to measure the speed of passing vehicles. A stationary radar gun emits EM radiation, a proportion of which is reflected from the target vehicle which is moving away from the gun at 'u' ms^-1. a)State the frequency at the target vehicle (f.tar) in terms of...
  27. M

    Finding Recoil Velocity of gun

    Hello, I am not sure if this thread is still active but I am doing the same kind of physics problem for homework, and I think I have come to a conclusion from all the helpful stuff on here, but just wondered if someone can check it over for me? This is not in my GCSE syllabus - my physics...
  28. H

    Finding Angular Velocity of Man with Gun in Physics Textbook

    Homework Statement This is a question from the physics textbook Don't Panic Volume I, chapter XIV. A man, mass M, stands on a massless rod which is free to rotate about its center in the horizontal plane. The man has a gun (massless) with one bullet, mass m. He shoots the bullet with...
  29. T

    Rail gun and magnetic field question

    Homework Statement The planet Zargon has a magnetic field that is oriented the same as Earth’s, but has a magnitude of 1.26 T! A Royal Zargon Warrior is exploring the Badlands at the Zargon equator when he senses that a vicious octomorph is on top of the rock pillar 9.50 m above him. He dare...
  30. J

    Find spring constant, unknown projectile mass, vertical spring gun.

    What I have given is: A projectile with an unknown mass is launched 90 degrees vertically to a height of 0.650 m with a spring deformation of x = 0.031 m. The initial speed of the projectile is v0=3.6 m/sec and the projectile is resting on top of the spring gun "holder" before launch. Find the...
  31. B

    Rail Gun type problem - find distance of particle traveled with minimal data

    Homework Statement Hello. I want to help a friend solve a problem. I'm having trouble finding the right way to solve for distance for this problem. I am given 2 parallel wires connected by another wire or perhaps a conducting fuse. His information is kind of vague, sorry. The current goes up...
  32. T

    Finding Theta: Aiming a Gun Between Two Ships

    Homework Statement Two ships are traveling parallel to each other in opposite directions with seed v1 and v2. One ship fire on the other. At what angle should the gun be aimed at the target ship in order to make a hit if the shot is fired at the instant when both vessels are on the straight...
  33. D

    Find velocity of gun and bullet on frictionless surface

    Homework Statement A 30.0-kg gun is standing on a frictionless surface. The gun fires a 50.0-g bullet with a muzzle velocity of 310 m/s. a) calculate the momenta of the bullet and the gun after the fun was fired. b) calculate the kinetic energy of both the bullet and the gun just after...
  34. F

    Help with Coil Gun for High School Physics Project

    I am making a coil gun for my high school physics project and I am running into some issues. I am using 400 turns of 36 gauge wire wrapped around a 1.25in diameter PVC pipe to propel a 1 inch diameter steel ball. I started with a 6v battery but that didn't move the ball at all even with...
  35. Evo

    Silence Gun: Strange weapon of the future

    I wonder if this is for real? I can see it being a popular item for married couples, and teachers. continued... http://news.yahoo.com/blogs/technology-blog/weird-gun-future-attacks-words-not-people-193050045.html
  36. C

    How does a radar gun determine velocity?

    Homework Statement Radar guns emit radio waves. The radar gun measures the beat frequency between the returning waves. How does the radar gun determine velocity? A. By measuring beat frequency between two consecutive reflected waves. B. By measuring the beat frequency between a wave...
  37. A

    Projectile Motion Time Calculation for Big Bertha Gun in World War I

    Homework Statement 7. During World War I, the German army bombarded Paris with a huge gun referred to, by the Allied Forces, as “Big Bertha.” Assume that Big Bertha fired shells with an initial velocity of 1.1 x 10^3 m/s [45° above the horizontal]. (a) How long was each shell...
  38. P

    How to Remove Electron Gun from CRT?

    Hey... I was just thinking... Does anyone know how to extract the electron gun from an old CRT so that it is left intact? Basically, I want to remove it so that I can play with the electron beam/use it for other experiments/ etc. Please tell me.
  39. T

    Air equivalent of rail gun possible?

    If a rail gun works by having an object that moves along a path, where either side has opposite charge, could that same principle be applied in air? I am not talking about an ion thruster, that already exists. I am saying, if wasting energy was not an issue, could it be possible to charge the...
  40. C

    Ball fired out of a spring gun differential equation

    Homework Statement You're firing a ball of mass 10.0g out of a spring gun, and the spring is the entire length of the barrel, which is .05m long. The force constant for the spring is 500 N/m. There is a constant resisting force of 10.0N acting on the ball as it travels down the length of the...
  41. B

    How far does the dart travel horizontally?

    Homework Statement I need help with the very last of a series of questions: The potential energy stored in the compressed spring of a dart gun, with a spring constant of 66.00 N/m, is 0.76 J. Find by how much is the spring is compressed. My correct answer: 0.152 m A 0.190 kg dart is...
  42. W

    Question About Cooling Rate in Gun Barrels

    Conventional thought in the gun forums is that a rifle barrel that is smaller in diameter will cool faster than an otherwise identical gun barrel that is larger in diameter, after the same number of shots fired. Is this true? I have trouble understanding how it could be since the larger...
  43. E

    What is the maximum range of a projectile gun with a speed of 315m/s?

    Homework Statement A gun fires a shell with a speed of 315m/s. Neglecting the effects of air resistance, calculate the maximum range of this gunHomework Equations t=(vf-vi)/a v=d/t The Attempt at a Solution it doesn't give me an angle so I am kind of confused on how to solve this problem. I...
  44. M

    So, I'm building a coil gun

    ...and need some help with a bit of engineering. I've got 5 2200μF capacitors @ 400V (I'm familiar with high voltage + current, just not inductors, and have the appropriate safety gear) in parallel with about .05Ω ESR a piece. These are running into a GE C150 SCR, which can surge up to 1200...
  45. 1

    Projectile motion of a fired gun

    Homework Statement A projectile is fired horizontally from a gun that is 99.0 m above flat ground, emerging from the gun at a speed of 250 m/s how long is it in the air? how far does it travel horizontally? vertical component of velocity as it strikes the ground? Homework...
  46. L

    Do Bullets Fired Upwards Pose a Risk When They Return to Earth?

    Apologies if this is the wrong forum but it's certainly a physics question I've been wondering about: I've been watching all this Libya stuff unravel on the news and can't help but notice all these guys firing their AK47s vertically upwards. Surely that bullet should then return to Earth at...
  47. M

    Flowfield visualization of a gun shooting underwater high speed video

    I ran this experiment to find out what a gun would look like while shooting under water. Turns out to be quite interesting. The muzzle blast is NOT spherical as I first assumed. Regards, Mrpennywhistle
  48. K

    A spring loaded gun question from my test.

    A spring loaded gun question from my test. Please Help! Homework Statement Suppose a .16kg mass on a spring loaded gun that has been compressed .10 m has elastic potential energy of .85 J. How high above the spring's equilibrium point can the gun fire the mass if the mass is fired straight...
  49. C

    Hoppe's #9 gun solvent and Potassium Chloride

    Hello, my name is Rudy and this is my first post. I am a gun owner and I am wondering about how to clean my rifle and all the accumulated residue derived from my military surplus ammunition which has Potassium Chloride in the Primers. After shooting the rifle, the Potassium Chloride gets into...
  50. Y

    Effect of Gravity Well on Muzzle Velocity of Gun

    Let's say we have gun that fires a bullet at 1000 m/s horizontally when high up in a gravitational potential. Now we take the gun deeper into the gravitational well to a point where the gravitational redshift factor is higher by a factor of 4. Will the muzzle velocity be the same, faster or...
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