A Longshot Pulse Rifle is an advanced Pulse Weapon that utilises pulsed induction fields to propel lethal micro-bursts of plasma over extremely long ranges. A Longshot Pulse Rifle is a variant of the Tau Pulse Rifle, modified specifically for a sniping role. As such, it has a far further range and fires more focused plasma pulses, whilst maintaining a similar rate of fire to its standard counterpart. As a rifle-sized Pulse Weapon, it is only known to be used by Sniper Drones as their primary weapon. Lethal weapons capable of sending plasma pulses over great distances, a well-placed shot from a Longshot Pulse Rifle is capable of taking out any target.
Longshot Pulse Rifles were a lethal fruit of the Pulse Weapon technology first developed during the Tau Empire’s Campaign of Cleansing from 606.M38 to 792.M38, the first prolonged war of the Tau against the Orks. Whilst the Tau suffered many defeats early on, they were ultimately able to eradicate the Greenskins, thanks in part to the Earth Caste refinement of the first Pulse Weapons. As a result of this campaign, the Dal'yth Sept was successfully founded.
A Longshot Pulse Rifle is a long weapon, but 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 comprise a solenoid. When current is passed through them, these coils generate an electromagnetic field oriented along the barrel. At the front of the pistol are the weapon's two muzzles, just behind which is a circular apparatus similar in appearance to a bolt-head, that serves as 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.
The Longshot 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 plasma 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 electromagnetic 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 of the field is also aided by a bolt-like apparatus, which increases the field strength and therefore the range. The weight of the bolt also serves to dampen the recoil from firing. Without the electromagnetic field, the fired plasma would all dissipate at the barrel mouth, producing a weapon with a range of approximately twenty centimetres. As it is, residual energy and waste plasma, together with the heat produced by energizing the coil, necessitates two barrels to avoid overheating.
The power required to generate these immense electromagnetic 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 power pack, and can be recharged from the firer's suit or combat armour. 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 armoured targets are more heavily damaged. The electromagnetic 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 plasma projectile is launched is so extreme, that in some cases, it has been known to "light the air on fire".
- Codex: Tau (3rd Edition), pg. 19
- Codex: Tau Empire (4th Edition), pp. 29, 40
- Codex: Tau Empire (6th Edition), pp. 28, 46, 66-67
- Imperial Armour Volume Three - The Taros Campaign, pp. 80-81
- Rogue Trader: Into the Storm (RPG), pg. 121
- Deathwatch: Core Rulebook (RPG), pg. 366