Gauss rifle

Compiled overview of a Gauss Rifle, from various BattleTech game sourcebooks and fictional novels:

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Gauss Rifles are a true innovation in the world of projectile weapons. They do not use explosives to propel the projectile through the barrel, but rather use a system called a RailGun. The RailGun system was created in the 20th Century, but manufacturing problems stopped the project.

Usually, the projectile is propelled through a small explosion. This system created a lot of friction between the projectile and the barrel, reducing the projectile speed. Also, the projectiles charged small amounts of explosive, creating ammunition explosions from heat and enemy hits. The RailGun system tried to solve this problem with a series of electromagnetic sectors and a projectile electromagnetically charged oppositely. This system removed the friction and the problems related with the explosions, as the projectile became a big piece of metal. The study of this system was suspended due to the problem of high power consumption.

Modern day Gauss Rifles are the direct evolution of this system. Gauss rifles use the same system to propel the projectile, a nickel-ferrous slug, and use a series of capacitors to power the weapons. Thanks to the unlimited power that a MHD reactor mounted in the 'Mech torso can create, these capacitors can be charged infinitely.

The projectile coming from the ammo bin is introduced to a loading chamber, where a mechanism places the shell in the first section of the weapon's long barrel. The loading chamber (and the rest of the weapon) is divided from the barrel by a diaphragm. This diaphragm opens to let the shell pass, then seals the barrel to discharge the projectile. As described above, the projectile is moved by electromagnetic force, rather than the usual charge of gun powder. The barrel is composed of a series of electromagnetically charged sectors and isolation areas between these sectors. When turned on and off progessively, starting from the innermost sector to the outer one, the sectors propel the shell toward the barrel nozzle. Without friction and other slowdowns, the projectile can achieve a speed of Mach 5 or greater.

The sectors are powered by a series of capacitors placed behind the loading chamber. A power line goes from the capacitors to the barrel, where a ring, called a power ring, collects the energy and passes it to four power lines encircling the barrel; the barrel's power lines are named after the four cardinal points, north, south, west and east, due to their placement. The capacitors are connected to the main power line from the reactor. Due to the high amounts of power required by the capacitor, the power line of the Gauss rifle is unusually large for a ballistic weapon.

For maximum energy performance, the lines are designed to redirect all the unused energy to the energy banks, and a direct hit to any part of the Gauss rifle is likely to create a destructive feedback, directed toward the capacitors, which aren't designed to receive large amounts of residual energy. Such feedbacks destroy the capacitors and the entire rifle with a powerful explosion.

The final part of the rifle is composed by the coolant circuit and recoil absorbing system. The recoil system is the only piece of machinery that generates a large amount of heat, and thus is the only part connected to the small cooling circuit in the cannon's back. The systems are linked with a heat exchanger for facilitating the heat conduction.

As described above, the Gauss rifle is as powerful as it is dangerous, due to the energy feedbacks. However, the explosion created by an overloaded capacitor is weak compared to the catastrophic explosions of normal ammunitions.

Technological differences made the Inner Sphere Gauss Rifle heavier and bulkier than the Clan version. These two versions have the same range and heat profiles. The Free Worlds League tried to duplicate the same structure used in the Clan model. Although this effort was not successful, they did create the so-called Light Gauss Rifle.

This version of the rifle works in the same way as normal rifles, but the Light Gauss employs a smaller and lighter shell. The shell reduction enabled the scientists to use smaller capacitors to power the rifle, therefore reducing the explosion created by the energy feedback.

The shell used by the Light Gauss travels faster in the barrel, increasing exit speed and the range covered. Also, the small size allows a 'Mech to carry twice as many rounds in a single ton, though the damage is reduced by 45%.

This is a way to build an awesome magnetic rifle for under 30 dollars.  Once you get all of the materials, it shouldn't take more than a half-hour to build.

What is a gauss rifle?

A gauss rifle is a device that takes advantage of a magnetic chain reaction to accelerate a projectile to high speeds.  As explained below, the concepts of magnetism and conservation of momentum allow this really cool technology to work.

There is a lot of confusion surrounding gauss rifles; the word is often seen as interchangeable with "coilgun" or "railgun," which are in fact two separate technologies.  Much of this confusion is caused by videogames such as Mechwarrior or Quake.  A good rule of thumb is: anything you hear about gauss rifles, coilguns or railguns in a video game is probably wrong.

A gauss rifle uses a series of fixed magnets that work in sequence to accelerate a ferromagnetic (i.e. sticks to a magnet) projectile.  On the other hand, a railgun uses a current-carrying substance placed in a constant magnetic field, while a coilgun accelerates a projectile in the center of a coil of wire, or solenoid.  Both railguns and coilguns are much more complicated than gauss rifles, which I will be focusing on here.

Materials

You will need 4 neodymium gold-plated permanent magnets (12mm), 9 steel ball bearings of 1/2 inch diameter or similar, a wooden ruler with groove in the center, and strong tape.

Neodymium magnets and ball bearings are tricky to find if you don't know where to look; your best bet is probably on science hobby sites.  I use www.scitoys.com, just search for "gauss rifle" or "magnets."

WARNING: Neodymium magnets are incredibly powerful.  Keep the four magnets well separated from each other prior to securing them firmly to a fixed surface.  If allowed to crash into each other, these magnets will probably shatter.

 Construction

1. Using a marker, put four equally spaced marks on the ruler.  If this is done correctly, you should have divided the ruler into 5 equal sections.

2. Place one of your magnets on the first mark you made.  Make sure that the sides of the magnet are parallel to the sides of the ruler.  Then tape the magnet VERY securely to the ruler.  Don't be shy, use 3 or 4 turns of tape.  That magnet is going to be taking a serious beating very soon, so make sure it's not going anywhere.  NOTE: Don't use glue to affix the magnets to the ruler; this keeps you from being able to play around with the design later.

3. Repeat Step 2 three times for the remaining magnets, placing each on the next mark.

 4. Pick a front end and a back end of your ruler.  This is arbitrary; it just makes the next few steps easier to explain.  You will start the reaction from the end, and the final projectile will come out the front.

5. Place two ball bearings in the groove in front of your front-end magnet. They should line up and stick to the magnet.

6. Repeat step 5 for the remaining 3 magnets.  You should have 1 ball bearing left.  Your construction should look like this:

I______#OO_____#OO_____#OO_____#OO_____

(where ____ is an empty section of track, # is a magnet and O is a ball bearing.  Please excuse the awful diagram.)

7. Place your construction on a flat, level surface and point the front end away from people, lamps, small animals, large animals, delicate objects, and things you do not want broken.  This rifle shoots the ball bearing at a very high speed, and if you're not careful you may get a nasty surprise.

8. Place the last ball bearing in the groove on the end of the ruler.  It should roll towards and strike the end magnet, starting the chain reaction that fires the rifle.

To ready the rifle for its next firing, replace the 8 internal ball bearings in their original positions.  Repeat step 8 to fire again.

Explanation

 When the last ball bearing is released, it is attracted to the end magnet.  It therefore accelerates towards and then strikes the end magnet. 

IO-->___#OO____#OO____#OO____#OO____

The momentum is then transferred from the ball bearing through the magnet to the ball bearing on the other side.  This momentum causes the new ball bearing to break away from the magnet and move towards the front. 

I______O#OO-->__#OO____#OO____#OO____

However, there is another magnet in its way.  It accerates towards this magnet, then hits it, repeating the process. 

I______O#O____O#OO-->__#OO____#OO____

This continues for however many magnet/ballbearing stages you stick into the gauss rifle.  Once you get to the last ball bearing, however, it simply leaves the rifle at a high speed after recieving the momentum from all the other stages.  This, in effect, "fires" the last ball bearing out of the rifle.

I______O#O____O#O__-->O#O__-->O#O____O-->

Using these magnets and messing around with different configurations, I have managed to put a small hole in the concrete wall of my basement.  Try different setups and see which works best.

What I have described here is a very simple kind of gauss rifle that isn't terribly efficient.  You lose a lot of energy because each ball bearing, as it is speeding up, is slowed down somewhat because there are magnets behind it pulling it back.  This problem can be solved, but requires a much more involved and complicated design.  A setup involving pulsing electromagnets seems to be the most promising way of addressing this issue.

Gauss rifles are still troublesome enough that many military research programs have abandoned related projects due to inefficiency or severe battlefield limitations.  However, it is likely that the problems involved with producing an effective gauss rifle will be solved in time.  In such a case, make sure you are the first person on your block that gets one.