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. wolram

    Australian Gun Reform: Interesting Study

    Interesting study about gun control in Australia. https://www.sciencedaily.com/releases/2016/06/160622114743.htm
  2. Planobilly

    Advice on heat gun temp for de-soldering

    This is more of a general question about what temps you set your hot air gun. I just got a new rework station and messed around with it for a bit on a old PCB removing large and small components. I find it easy to damage the PCB. In general I tend to solder pretty hot, anywhere from 300C to 400C...
  3. 1oldman2

    Alternate uses for rail gun technology

    After reading the following article and watching it's accompanying video I'm left wondering if the technology could be used for other projects than military. I understand that military programs account for many useful (as well as profitable) commercial ventures, but this one has me wondering...
  4. S

    CO2 Air Gun: Can JB Weld Withstand the Pressure?

    I am trying to make a CO2 air gun and was wondering if jb weld can hold the pressure from the 12g CO2 cartridge in this set up with a CO2 bike pump connected to a valve that can wothstand the pressure
  5. C

    Water gun problem, pump stroke -> pressure

    Hello all, I have a question about a water gun problem I'm working on. The general question is...how can you associate the hand pump stroke length, and the diameter of the pipe the pump is inside, with how much pressure gets built up in the guns pressure chamber?
  6. C

    Finding velocity and momentum of a bullet and recoiling gun

    Homework Statement A bullet leaves the barrel of a gun with a kinetic energy of 90 J. The barrel of the gun is 50 cm long. The gun has a mass of 4 kg, the bullet 10 g. (a) Find the bullets final velocity. (b) Find the bullets final momentum. (c) Find the momentum of the recoiling gun. (d) Find...
  7. P

    A How much energy dissipated in a nail gun?

    Hi all, I'm having trouble working out how much energy will have to be dissipated in a test rig for a nail gun. From previous testing, I know that a test slug fired from the gun has a mean energy of 100J. I now want to design a test rig which can fire the gun repeatedly for 100,000 shots. I...
  8. A

    Gaussian gun: Where does the extra kinetic energy come from?

    Probably a stupid question, but I do not get it... Here you can see an experiment demonstrating the Gaussian gun: Here I understand how momentum is conserved, i.e. the smaller mass of the ejected ball times its high speed is equal the bigger total mass of the recoiling masses times its...
  9. L

    A shot fired from gun, elevation to hit a target 3000 feet away

    A shot fired from a gun with a muzzle velocity of 1200 ft per second is to hit a target 3000 feet away. Determine the minimum angle of elevation of the gun? Ok so I know that r(t)= (vcos(theta) t)i +(vsin(theta) t +16t^2)j I tried to set vcos(theta)t =3000, solve for t, and plug into the j...
  10. M

    Does initial speed of a gun affect bullet velocity?

    My brother and I were having an argument so I decided to make an account on this forum. Say you were to lurch you hand forward while firing a pistol. Would that affect the max velocity of the bullet?
  11. Y

    Would a gun with this barrel shape generate less recoil?

    I was wondering whether the following gun barrel shape would generate less recoil. Imagine that we have a bunch of L-shaped pipes which are closed on their long end and open on their short end. Take 4 of these pipes, and join them up along their short parts so that they form a plus-sign shape...
  12. G

    Tennis ball gun, muzzle velocity

    I am designing a tennis ball gun and am trying to work out the forces involved. It is essentially elastic powered but at this stage all I need to know at this stage is this: with the gun at a 20 degree incline what muzzle velocity would result in the ball traveling 50 metres?
  13. RandyD123

    Bullet Velocity Experiment: Does a Fired or Dropped Bullet Hit the Ground First?

    If a bullet is fired from a gun perfectly parallel to the ground and a bullet is dropped from that same height at the same time which one hits the ground first? Sorry for the two late edits. 1. The gun is not dropped, the gun is locked in a vice and perfectly level to the ground. 2. The bullet...
  14. M

    Distance and speed in spud gun

    Homework Statement I have to calculate the speed with which a spud gun fires a bullet. The length of barrel is 1 meter. Homework Equations v=s/t , where v=velocity; s=distance; t=time The Attempt at a Solution NOTE: I will easily calculate distance. I have spud gun but I don't know the way...
  15. L

    How many bullets does an astronaut need to fire to return to the space shuttle?

    Homework Statement An astronaut is drifting away from the space shuttle at a velocity of 1.1m/s. He fires his gun's 30g bullets to return to his ship. The mass of the astronaut and his spacesuit is 123kg, his gun has a mass of 12kg and the bullets leave the gun at a velocity at 250 m/s. What is...
  16. jpcyiu

    A gun of mass M fires a shell of mass m and recoils horizont

    A gun of mass M fires a shell of mass m and recoils horizontally. If the shell travels with speed v relative to the barrel, find the speed with which the barrel begins to recoil if (a) the barrel is horizontal (b) the barrel is inclined at an angle A to the horizontal.
  17. kostoglotov

    A tuning fork measured by a police radar gun

    A police radar gun emits radio waves at 10.5 GHz, and measures the beats between this frequency and the returned waves to determine the speed of an object. It registers a tuning fork as "traveling" at 24.6 m/s. What is the frequency of the tuning fork. I can get the answer, but I don't...
  18. P

    How to remove electron gun from a TV?

    I'm trying to reuse an electron gun from an old black & white TV for an art project. I've posted into this forum rather than Electrical Engineering as I think that this is a strictly mechanical matter with no electricity involved. The TV's dead, and all I want is the physical bits of the...
  19. N

    What is the safest way to focus a powerful laser for a homemade laser gun?

    Hello, I am Noctua and i have 14 years old :D So, today i had the idea of building a sort of non powerful laser gun.I plan to focus the light with converging lens.I will use a powerful laser Pointer.So, here is my questions: If I absurdly concentrate a laser , the concentrated light would be...
  20. T

    Microparticle Transport via Directed Particle Gun

    Greetings PFers, Would it be possible to move microscopic particles of a wide range of composition (conductivity, density, etc...) using a directed beam technology? The idea is to have a fast 3D printing technology (practically no moving parts) that is capable of depositing of a wide array of...
  21. Comfort_Cube

    Is this correct reasoning? Questions on the physics of pneumatic spud gun.

    I'm building a pneumatic spud gun, and am thinking about the volume of the muzzle/barrel. It will be cylindrical (a pvc pipe). The projectile will either be a spherical or cylindrical object (same mass). The muzzle will be connected to the air chamber via a sprinkler valve. So, the aim in this...
  22. jlefevre76

    Understanding the Physics of a Coilgun: A Beginner's Guide

    Hey, I've seen a few posts on this without any responses I really thought helped (at least help answer my question). So, I was hoping somebody on the forums here could help walk me through the basic physics of a coilgun. Basically, how could you characterize the magnetic field inside the...
  23. G

    How does the circuit in a stun gun produce high DC voltage

    How does a stun gun or a fly swatter circuit produce DC voltages that are at least 2 or 3 orders of magnitude higher than the single 9 volt DC battery used to power the device. I would appreaciate if someone can give me some information regarding the sort of components/circuits that are used to...
  24. E

    Proof of 2v Velocity When Gun Fired Aboard Plane

    If a gun fires a bullet at a velocity v and is then taken aboard a plane traveling at a velocity v and is fired again in the direction of travel ,what is the simplest proof that the bullet's new velocity is now 2v ?
  25. D

    Physically measuring forces of gun recoil

    I want to measure the forc e of an AR15 recoiling over time from a single shot. The gun cycles at about 900 rpm, so the recoil impulses should be over within 67 miliseconds. There are two different parts to the recoil impulse. Within less than a milisecond, there should be a large impulse that...
  26. D

    Would changing the weight of gun components affect recoil?

    This question really does the need assistance of somebody trained in physical sciences. I've asked countless gun people and they are very opinionated but few of them can put forward answers that show they know anything about physical science. I myself dropped out of Engineering school halfway...
  27. B

    Need Help Projectile Motion - Hitting Target with toy gun

    Hey, I need help with a lab I'm doing in class. The goal is to hit a target on the ground by shooting a bullet from a toy gun. Our distance from the target will be assigned to us by our teacher and I need to calculate the initial velocity of the gun and then hit the target by only changing the...
  28. R

    How can you accurately find the initial velocity of a toy gun?

    Disregarding air resistance, how could you find an accurate number for the initial velocity of a toy gun?
  29. M

    Engineering Dynamics: Find gun initial recuperator force to limit recoil

    1)The breech and barrel of a field gun have a total mass of 453.6kg. The recoil of the barrel is controlled by resistance forces from a buffer and recuperator, these forces are given by: Buffer force=71000/(s+1), recuperator force= P+ 4380s. (both are in Newtons). s is the recoil of the barrel...
  30. D

    Toy Gun Spring Compression and Projectile Height: How are they Related?

    Homework Statement There are two problems, but I think that they are similar: A toy gun shoots a projectile straight up. The maximum height reached by the projectile is H when the spring is compressed x cm. For the projectile to reach a height of 2H, the spring of the gun should be compressed...
  31. Emily_20

    What Is the Average Force Exerted by a Recoiling Shotgun?

    Homework Statement A 0.031 kg bullet is fired from a shotgun of mass 3.63kg at 420 m/s. If the collision of the recoiling gun with your shoulder takes 0.013s, what is the average force the gun exerts against your shoulder? Homework Equations p = m • v[/B] vf=vi + at F=ma The Attempt at a...
  32. A

    Electromagnetic Rail gun and a circular track

    Two parallel electromagnets situated symmetrically on either side of the straight section of an oval track propel a wheeled trolley along the track, so that the trolley is in continuous motion, as long as the current is supplied to the electromagnets. Is this workable? Does the entry and exit...
  33. A

    Semicircular Permanent Magnet Rail Gun - continuous motion?

    Doubtless you are all familiar with a rail gun made by using permanent magnets. An example is given here: http://sci-toys.com/scitoys/scitoys/magnets/gauss.html Assuming the railgun could me made curved, won't it be possible to build a curved track to transport the projectile - assume...
  34. L

    Kinetic Energy of bullet fired from gun

    Hi everyone. I'm quite troubled with this physics question. A .035 kg bullet is fired from a .23 m barrel. The bullet experiences a force of 4500 N while in the gun barrel. What is the kinetic energy of the bullet as it leaves the gun barrel? I don't understand how to figure out the...
  35. U

    Explosion force inside gun barrel

    When I fire a gun there is an explosion inside a barrel that causes bullet to fly and gun to recoil but when a barrel is blocked a whole gun can explode, does it mean explosion inside barrel is stronger in second case?(The reason why I am wondering about it is because forces of explosion press...
  36. A

    Projectile Motion Gun Problem: Calculating Elevation Using Equations of Motion

    1. Homework Statement : A gun is fired from a moving platform and the ranges of the shot are observed to be R and S when the platform is moving forward or backward respectively with velocity V. Prove that the elevation of the gun is tan(inverse)[g(R - S) ^ 2 / 4V ^ 2(R + S)] 2. Homework...
  37. BrainMan

    Machine gun conservation of momentum problem

    Homework Statement A machine gun held by a soldier fires bullets at the rate of three per second. Each bullet has a mass of 30 g and a speed of 1200 m/s. Find the average force exerted on the soldier. Homework Equations FΔt = mgf-mgi The Attempt at a Solution I attempted to do this...
  38. A

    Why do magnets in a Gauss gun exhibit backward drift after being hit?

    So I was building a Gaussian gun for physics filming it at 300fps. See video: http://youtu.be/hZcAk3uBp58 While skipping frame by frame, I realized that all the magnets started drifting backwards after being hit. Can someone explain in detail what is going on? Sorry if my physics is not...
  39. D

    Can a electron gun attract/repel permanent magnet?

    Can it do such a thing or are the particles too small ? If it is possible can I take the electron gun out my cry is you AA batteries?
  40. P

    Coil Gun: How It Works & Physics Behind It

    What is the physics behind coil gun. For the magnetic field part, that is convert a electric voltage to the magnetic field. How the magnetic field related to the voltage? Is there any equation for the conversion the voltage to the magnetic field, maxwell or others? After that, the...
  41. 0

    Shooting a .45 caliber hand gun on the moon launches you a mile?

    Shooting a .45 caliber hand gun on the moon "launches" you a mile? My co-worker and I were having a discussion about an activity that he did while at a teachers math conference. The activities was to rate the importance of objects. There were 15 objects and you are stranded on the moon 200...
  42. parazit

    High Repetitive Photocathode RF Gun

    Hi fellows, I've been looking for "High Repetitive Photocathode RF Guns" for more than a couple of days. It seems, first I need to understand the RF Guns. I deciced to search such a document that gives the history of RF Guns and explains their historical background with working principle...
  43. Crazymechanic

    Youtube rail gun videos physics

    So I once saw a intersting video made by some guys for a school project , now I finalle decided to have a share with you and ask some question. Such videos are also put up by the free energy guys but let's not focus on that for now shall we. https://www.youtube.com/watch?v=Vo2-Qb3fUYs...
  44. dlgoff

    Cops stun gun father trying to save son

    What do you think? http://www.guns.com/2013/11/04/cops-stun-gun-father-tries-rush-burning-building-save-3-year-old-son-video/
  45. T

    Calculating Zenith Angle for Nerf Gun Targeting

    I'm working on my engineering capstone design and part of our design requires a code we have written to calculate the appropriate zenith angle for a nerf gun to fire a projectile so that the dart hits a certain target. We are feeding the code a target coordinate (x,y,z). One section of our...
  46. X

    Conservation of Momentum of railway gun

    The largest railway gun ever built was called Gustav and was used briefly in World War II. The gun, mount, and train car had a total mass of 1.22·106 kg. The gun fired a projectile that was 80.0 cm in diameter and weighed 7502 kg. In the firing illustrated in the figure, the gun has been...
  47. H

    Use of alternate energy to load a gun

    Can someone help me regarding a concept in gun mechanism?? In the current mechanism a part of the chemical energy of the gunpowder is used to load the next bullet.Had this energy not been used to load , would it increase the range of the gun?? and if so, then is the increase significant??
  48. D

    Building an efficient coil gun for photography.

    I have been doing various experiments with my photography and recently built a coil gun. I simply pulled apart a starter-motor solenoid and wrapped the windings around an 8mm tube and fire a short piece of a bolt out of it using a charged 3300uf capacitor and an SCR. None of this is calculated...
  49. J

    Calculating Speed with a Radar Gun: Exploring Doppler Shifts

    Radar Guns are used to measure the speed of a moving object. The wave it emits experiences two Doppler shifts. How does the radar gun then use the difference in frequency of the initial wave it emits and the frequency of the final wave it receives to calculate the speed of the object...
  50. J

    What materials are transparent to radar? Weatherproofing a radar gun

    I’m currently working a project to produce a roadside speed camera which displays vehicle speed to drivers to improve speed awareness. A Doppler radar gun operating at 24.1GHz (1.24cm) is being used as the source and detector. There is a weather tight plastic box (opaque, at least to visible...
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