From Black Mesa: Wiki

High quality render and view model of the Tau Cannon.

Overview

The XVL 1456, conventionally known as the Tau Cannon, is a prototype particle-accelerating weapon developed in the Advanced Biological Research Lab of the Black Mesa Research Facility. It can be first procured by the player in the chapter Questionable Ethics.

The Tau Cannon fulfills the role of a superweapon, propelling tau particles at incredible speeds with enough energy to destroy armored vehicles and aircraft at long ranges with excellent accuracy. Firepower must be used sparingly as each shot depletes the weapon's reserves relatively quickly, and its ammunition is very rare.

The Tau Cannon's secondary function fires the weapon at half the ammunition cost, but at a slower rate. Holding the function charges the weapon for a more powerful blast with a higher ammunition cost. The gravity of these statements increases the longer the secondary function is performed until the process is completed.

Operator Beware: Holding the Tau Cannon in a fully charged state for an extended period of time will cause weapon failure, resulting in serious injury to the user as thoroughly demonstrated by the previous owner.

Author's note: * denotes a tentative placeholder value.

Primary Function

Ammunition: Depleted Uranium (2*) , Hitscan

Damage: 20* , Point-of-Impact

Rate of Fire: ???ms*

Weapon is not fed by the player.

Reserve pool capacity of 100 units, shared with the Gluon Gun.[1]

Secondary Function

Damage: 20-200* , Point-of-Impact

Rate of Fire: ???ms*

Weapon is not fed by the player.

Reserve pool capacity of 100 units, shared with the Gluon Gun.

Hold to charge.

Media

The Tau Cannon model.

An in-game screenshot of the Tau Cannon.

Trivia

• The Tau Cannon is also commonly referred to alternatively as the "Gauss Gun". This is because of the original use of the weapon; When Valve turned it into an experimental energy weapon partway through development, they neglected to change the name in the code.