Psycannons are based on the boltgun, firing bolts heavily impregnated with negative psychic energy. The bolt is devastating to the psyches and physical bodies of psykers, daemons, and the possessed. As if the negative psychic energy was not enough, each psycannon bolt is also silver-tipped and inscribed with anti-daemonic symbols.
A Grey Knights Terminator armed with a psycannon can fire it at full effect even when on the move.
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 mental intent. This has the advantages 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 ammunition count or barrel temperature. In addition, if the user is a psyker, they can infuse their own power with that of the weapon, adding to its already devastating effect.