This page may be a little cryptic or make little sense, it's where I jot down some of the idea's I want to achieve, although I may not give all of the details if potentially it gives others opportunity to make money from them. Please note that these are only ideas, I have not built them and may have only gone to the extent of desiging a few ideas.
Ok, so I do have quite an interest in guns, mostly in how they work but really most of them are all the same. Take for instance the 9mm parabellum FMJ, it will do 390m/s at an energy of 570J, you pick any 9mm gun and it will have this ballistic performance. The only real difference between all of the guns is that they have different rates of fire, accuracy, weight and ergonomics. Now all of these factors play into one-another, it mostly comes down to preference, this is why 100 year old designs are still been used. I must note that the ballistic performance can also vary slightly with barrel length, I'm talking in general.
More talk on ammuntion, so there are quite a number of commonly used munitions in the military, the table below shows some of them;
|9 x 19 Parabellum||Small arms||390m/s||570J|
|5.56 x 45 NATO||Rifle / Sniper||991m/s||1974J|
|7.62 x 39||Rifle||730m/s||2108J|
|7.62 x 51 NATO||Sniper Rifle||838m/s||3275J|
|7mm Remington Magnum||Sniper Rifle||950m/s||4050J|
|.300 Winchester Magnum||Sniper Rifle||950m/s||5400J|
|.338 Lapua Magnum||Sniper Rifle||900m/s||6600J|
|50 BMG||Anti Material Rifle||920m/s||18000J|
Apart from the parabellum all of the rest are for rifles, half-way down the list for sniping rifles. The effective distance of these bullets increases as their energy does but with increasing energy you have to increase the pressure behind the bullet, it means a bigger cartridge, more pressure, a stronger build and then a higher weight. Considering the average 50 BMG rifle your talking about 14kg in weight, it does however help steady the gun and remove recoil, so a heavier weight can actually be benefitial. The most common sniper round is infact the 7.62 NATO with an effective range of about 800m. Although now becoming very popular are the .300 and .338 Magnum's, these rifles weigh on average 7kg.
So what does all of this mean, well the 50 BMG is only capable of firing this amount of power comfortably due to the recoil reduction it has in place, it is significantly heavy and really is overkill when a rifle half the weight has the same effective range, this is if used as an antipersonel rifle. What is the point in creating anything else when these do the job just fine, well in many instances this is true but what if there was a rifle with a faster bullet velocity, say double, this would provide a huge advantage as projectile drop would be less and therefore greater accuracy at range would be possible. These guns also produce a huge amount of noise and muzzle flash, these can be erradicated but also add to the weight and dimesions of the gun.
A gun that is powered electromagnetically can produce incredible velocities, 2000 m/s plus whereas chemical propellants struggle with more than 1100 m/s (some special cartridges will do up to 1500m/s, the guns have severly limited life). It would be completely silent, well apart from breaking the sound barrier, pose no transportation hazards with munitions and could in theory be lighter in weight. So why hasn't it been done, well it has, coilguns and railguns. Coilguns and railguns are great for artilery as they can cover great distance at great accuracy, with the velocity being so high they cease to need a payload. So why hasn't it been done on a smaller scale, well these large cannons use huge bulky capacitor banks, some hobbyists have made hand-held ones, even I did when I was about 15, it held 500J and had kinetic energy of 20J, not very portable either.
Hobbyist coilguns use a solenoid with few turns and dump a high voltage capacitor across it to pull a ferromagnetic projectile into the middle of the coil, by this time the capacitor has discharged and the projectile continues. This is completely the wrong way of doing it as the ferromagentic material saturates and there is a limit to what velocity it can be accelerated to even with multiple stages. I managed an efficiency of 2.5% for my coilgun which is considered to be very high, I managed 8% efficiency with a 1kJ induction launcher I built. The only way to get the high velocities is to use induction, it's exactly how the large military coilguns work. It works by the coil inducing a current in an aluminium or copper ring, this ring is the projectile, the current induced in the ring produces a magnetic field which reacts with the coil, it repels and forces out the ring at a substantial speed. Another problem is that hobbyist coilguns use electrolytic capacitors at around 300V, they simply cannot provide high enough currents, normally less than 1% efficient. My coilgun ran at 500V and doubled this efficiency, my induction launcher ran at 900V and more than triple efficiency. The military runs theirs at 20kV using film capacitors along with multiple stages and achieves a 20% efficiency, this was a paper from the 90's so they should have doubled this by now.
So why do I think I can do better, well I have thought up where I can make improvements to the coils and the power source. For instance an electrolytic capacitor cannot be used, it may hold the most energy per kilo but simply the ESR is too high to provide a high enough current. Film capacitors with low ESR are perfect but only yield a storage of 1.5kJ per kilo, clearly far too low to be of any use. My energy storage method will be about 2kg and hold 160kJ of energy and be able to discharge the majority of power in less than a milisecond. Even if my system was to be 2% efficient, the gun would still yield 3.2kJ with a total weight of 4kg.
The first step would be to determine what size the projectile should be and what weight. A projectile at 2000m/s is going to have four times the energy than one moving at 1000m/s, this means that the weight would need to be reduced. The larger the projectile the more efficient it will be but will suffer more in ballistic terms with it's lighter weight. The idea is to find out what energy the Laupa round holds at 1500m which is the maximum effective range, I then must calculate a projectile size and weight on that. A lapua Magnum will have 850J at 324m/s left at a range of 1500m, therefore my projectile shall finish at this energy, the speed will be higher due to the lower weight of the round. Now due to the obscenely low density of my projectile it would mean that the velocity would drop off very fast if it were to be shaped like a Spitzer round, the only way to get around this is to use a tubular shaped projectile, infact it needs a tubular ring in order to work, copper being the choice due to it's relatively high density and conductivity. The projectile would have a plastic insert with a fast helix, the air passing through would cause the rotation and therefore rifling in the barrel would not be needed, it would also have the same density compared to a full metal jacket and therefore similar trajectory.
It turns out that a 2000m/s projectile with the same ballistic coefficient as the Laupa with a total weight of 3.24gram (50 grain) would have 1024 Joules energy after 1500m with a velocity of 795m/s. It would have a 6500J of energy to begin with just like to Lapua but would have more energy and more speed at 1500m, it would also have six times less drop over that distance, thats a tremendous improvement. I may even be able to improve the energy it retains by making the projectile more aerodynamic such as an aerofoil design. Anyway all of this is just speculation, there is science behind these idea's and I'm pretty sure all of this would be possible. For now I can make some small scale tests on linear accelerators and I can also design and work on building a power supply. If scale tests work and my projections are accurate then maybe I could seek permission to scale it up. I do however find satisfaction in the theory and small scale experiments so scaling up isn't personally neccessary.