The Pulse Rifle is the main infantry weapon of the Tau and is commonly used by their Fire Warriors. They are also sometimes available to allied units, like Kroot Shapers. It has an extremely long range when compared to the main infantry weapons of other races, and also fires far stronger rounds.
The standard-issue Pulse Rifle is a very long weapon, with a length many times its width and height. The bulk of the barrel is surrounded by coils of conductive material, visible in some patterns along the top of the weapon, which produce a solenoid. When current is passed through them, these coils generate a magnetic field oriented along the barrel. At the front of the weapon are the weapon's two muzzles, just behind which is a circular, bolt-head-looking apparatus that serves a recoil stabiliser. Behind the barrel mechanism is the primary magazine, and behind that the trigger assembly and stock. Within the stock is the secondary magazine, or power cell. A scope adorns most models of Pulse Rifle, atop and slightly forward of the trigger assembly.
The Pulse Rifle works by electromagnetically accelerating a plasma shell down its barrel. In effect, it is a miniature mass accelerator. On firing, a ferromagnetic, solid slug is chambered from the magazine and turned into a plasma, most likely by electromagnetic induction, as it would be relatively easy to alternate the coil current at frequencies sufficient enough to heat the coil to an extreme temperature while keeping it in the chamber. The solenoid is then charged fully, propelling the newly produced plasma out of the gun at an extreme velocity while keeping it cohesive. Though this field continues to keep the plasma together until impact, residual plasma is expelled from the barrel to produce the weapon's considerable muzzle flash. Maintenance in the field is also aided by a bolt-like apparatus, which increases the field strength and therefore the range. Without the field, the plasma would all dissipate at the barrel mouth, producing a weapon with a range of approximately twenty centimeters. As it is, residual energy and waste plasma, together with the heat produced by energizing the coil, necessitates two barrels to avoid overheating; rapid-fire variations on the pulse rifle occasionally employ four barrels or more.
The power required to generate these immense fields comes from the secondary magazine which is effectively a very powerful and dense rechargeable battery in the weapon's stock. It is changed less frequently than the primary pack, and can be recharged from the firer's suit. Vehicle-mounted pulse weapons are usually connected directly to a suitable power source, allowing higher rates of fire with sufficient heat dispersal and eliminating the secondary magazine. Pulse weapon rounds do a great deal of damage on impact, mostly due to the extreme thermal energy of the plasma mass and the speed with which the projectile impacts, which helps ensure that armored targets are more heavily damaged. The magnetic field that holds the charge together flattens on impact slightly before breaking, which causes the resulting impact to spread over a wider area than would otherwise be possible. The speed at which the projectile is launched is so extreme, that in some cases, it has been known to "light the air on fire", due to it's velocity being somewhat close to the speed of light.
Compared to other infantry weapons, the Pulse Rifle trades firing rate for damage. When compared to a Space Marine Bolter, it appears to work more like a hand held artillery piece; firing at one-third the rate but doing significantly more damage and having a much longer range. Pulse Rifles also have significant recoil, which requires that the firer be stationary to fire most effectively. This, combined with its long range, means that Tau troops are best served by staying more or less stationary. They still retain most of their effectiveness on the move nonetheless, and can be devastating weapons when used correctly.
- Codex: Tau (3rd Edition), pg. 19
- Codex: Tau Empire (4th Edition), pg. 29
- Rogue Trader: Into the Storm (RPG), pg. 121
- Imperial Armour Volume Three - The Taros Campaign, pp. 80-81
- Games Workshop Website - Kroot Shaper