CLGGs provide performance as good or better than railguns through use of low molecular-weight combustible gases, such as hydrogen mixed with oxygen. The main drawback of these weapons are the complex firing mechanism, and the need to keep a large supply of Hydrogen and Oxygen around in their liquid forms.

This would make the guns infeasible for infantry or even small vehicles. Most large, modern, starships would also prefer to use their large reactors to power Railguns or Coilguns instead. However, there are a number of older designs usually from the early 2100s that prefer CLGGs as these space craft were often already carrying Hydrogen and Oxygen for use as propellant.

In the 2300s, CLGGs are a very mature technology but they are rarely seen outside of laboratories.

See: https://en.wikipedia.org/wiki/Combustion_light-gas_gun

The less famous brother of the Railgun... The Coilgun uses electromagnetic force to propel projectiles at high speed. Instead of passing a current through a projectile like a railgun, it uses magnetism and high speed electrical switches to attract/repel a projectile as it moves through a series of ring magnets. These weapons tend to be more energy efficient than a railgun and provide the same capability at a lower weight. They are also far more complex to build and require much greater precision and maintenance to maintain their capabilities.


Coil guns have a similar set of advantages and disadvantages as Railguns. They require a massive power source to function, as well as precision electronics. This makes them well suited to vehicles and starships that already carry large power plants. Generally the decision to use a railgun over a coilgun comes down to cost and maintenance concerns rather than performance statistics.

ETC guns use an electrical ignition system for propellant to more efficiently use propellant.

The increasing effectiveness of chemical propellants would increasingly make the limiting factor in handheld guns the amount of recoil a human could withstand, and increasingly reduce the mass of the round used. While ETC technology had become relatively mature by the 2100s, it was common for most militaries to stick with conventional firearms due to increased simplicity of the system.

See: https://en.wikipedia.org/wiki/Electrothermal-chemical_technology

Railguns use electromagnetic force to propel projectiles at high speed. They have gotten a reputation in popular culture for being able to fire projectiles at extreme speeds, though modern propellants and weapon designs like Light Gas Cannons can achieve similar performance.

The primary advantage and drawback of the Railgun is that it requires a massive power source. This makes railguns an extremely attractive option for vehicles and starships that already carry powerful generators. This allows vehicles to get far greater performance out of their weapon systems by powering them with the reactors that are also used for propulsion and other operations.

The handheld rifle has its origins in the 9th Century when a bamboo tube was used to fire a spear using gunpowder, but it wouldn't be until the 1940s that the weapon matured into the system that is familiar to most today. From the 1900s to 2300s the assault rifle would see incremental upgrades to optics, ergonomics, propellant, and firing mechanisms. Most recently Miniaturization and propellant advancements have made guided rocket rounds increasingly viable, with ETC initiated gyrojet rounds just starting to enter into wide service with organizations like the dàqín dìguó. Even unguided rifles can carry more ammunition, are lighter weight, and pack more power behind each round than weapons produced in the 21st century.

While electromagnetically propelled weapons have replaced gunpowder on nearly every combat platform, the handheld assault rifle still remains predominantly chemically powered due to weight concerns. Typically, a rifle with 200 rounds will be a lot lighter weight and easier to use than a coil gun + ammunition + power system for a human. Vehicles like starships and tanks tend to already have access to an abundance of electricity, which makes it easy to use rail or coil guns and carry the automation needed to operate it. Most modern militaries have an aversion to giving soldiers more complex weapon systems, and find the chemically powered conventional weapons more effective than their electromagnetically powered counterparts for most situations.

Also known as Gyrojet weapons, Rocket Guns typically refer to rocket launchers that use a similar form factor to other handheld rifle like weapons instead of the larger shoulder-launched systems.

The primary benefit of these weapons is being able to fire a projectile at high velocity with manageable recoil. Unlike conventional rifles where all of the acceleration happens inside of the weapon, forcing the user to absorb all the recoil, a rocket gun can spread its projectile's acceleration out over a great distance as the round will continue to accelerate on its own. This can provide better ballistic characteristics than even hand held railguns.

Despite the benefits, Rocket Guns tend to be much more expensive to operate than conventional firearms so they tend to appear only in small numbers.