The Pulsar-Fusil is a strange energy weapon mounted and utilized by the Cogboys of the Adeptus Mechanicus. These weapons usually mounted on a Krios Venator and is another weapon dating back during the Dark Age of Technology.
It is a multi-chambered particle beam cannon designed to fire volleys of destructive energy bolts which detonate explosively upon hitting their target, tearing armored vehicles apart with repeated strikes. It is unknown whether this weapon should be classified as a form of Plasma weapon, Conversion Beamer, Arc weapon or some esoteric Bullshit technobabble that the AdMech had pulled out lately.
But seeing how the Krios Venator is a tank destroyer, it would be believed that the type of energy released, like most Mechanicus weapons, are unstable, extremely volatile and absolutely lethal to whoever handling the trigger. The matter of the fact is, if we take its name literally, it could be analogous to the Tau's Pulse weapons. Or it could be a much larger version of the AdMech's Phased Plasma Fusil.