The bolt, called a "psybolt," is devastating to the psyches and material bodies of psychic creatures, such as psykers, daemons, and Daemonhosts, those individuals who have been possessed by the daemonic entities of the Warp.
The negative psychic charge and anti-daemonic ritual inscription on every Psycannon bolt allows them to pass through any defensive shielding, whether it is created by direct psychic energies or generated by manipulation of the Warp, technology employed by Void Shields or Conversion Fields.
The weapon has an anti-gravitic suspensor incorporated into its mechanism to offset the weight and this allows it to be fired on the move although at the cost of a reduced effective range.
The Psycannon is generally wielded with both hands by the Grey Knights who are assisted in making use of it through the efforts of their Power Armour. It is used with two hands by most other operators as well, although members of the Grey Knights' Terminator Squads mount the Psycannons on their arm instead.
The method of feeding ammunition is similar to that of the Heavy Bolter used by the Space Marines, which uses an ammunition belt running from the ammunition store located within the operators' armoured backpack.
The Psycannon can also be used in conjunction with a device called a Mind Impulse Unit. The Psycannon is linked to the mind of the user and is fired by his or her mental volition.
This has the advantage of allowing the user to fire the weapon while keeping both hands free, and allowing the user a greater intimacy with his weapon's internal workings, such as its current amount of remaining ammunition or its barrel temperature.
Also, if the user is a psyker, they can infuse their own power into the weapon, adding to its already devastating effect. This is a common technique used by the Grey Knights, the only Astartes Chapter comprised entirely of psykers.
These psybolts are less effective than the standard Psycannon's bolts, but more powerful than the same-sized bolts of a non-psychically charged weapon.
These weapons are similar to the standard Psycannon save that they possess a massive scale and power requirements can only be accommodated by a Nemesis Dreadknight.
- Codex: Daemonhunters (3rd Edition)
- Codex: Grey Knights (5th Edition), pg. 58
- Realms of Chaos: Slaves to Darkness (1st Edition)