A fusion-powered chainsaw which requires two hands to use. The weapon is heavy, but deals considerable damage because its continuous cutting action allows it to bypass Damage Resistance and Damage Threshold. Unlike most melee weapons, holding down the attack button when wielding the chainsaw will cause continuous damage to targets in contact with the blade.
The chainsaw's V.A.T.S. attack animation is unusual due to the automatic nature of the weapon type. The attack is initiated but the automatic damage is not applied, nor does the target act as if harmed, until the end of the attack when the damage is finally applied. It also has a slight knockback effect.
The chainsaw, along with the Ripper, is one of two weapons in Fallout: New Vegas that non-player characters use differently than the player character. Rather than using the thrust attack, they use the V.A.T.S.-style slash. This can cause a large amount of damage.
Despite making very loud noise when firing and having a static sound when just wielding, it is considered completely silent by the game, not drawing the attention of NPCs.
The damage and DPS displayed is counted for 1 second of continuous attacking. The critical damage, however, is counted for every damage tick. These ticks happen tens of times per second and, because of this, the chainsaw, along with other "continuous attack" melee weapons, is extremely strong with critical chance/damage bonuses. With no critical damage bonuses, the difference between 0% and 20% critical chance is double the amount of damage displayed. With 100% critical chance, the damage seems to be seven times the basic amount.
This weapon, like all other continuous attack close combat weapons, has only its "start-up attack" animation sped up by attack speed bonuses, while damage dealing and DPS is completely unaffected.
Due to an engine bug, the Ignore DT/DR effect does not apply correctly and because of this, Piercing Strike gives a marked improvement in DPS.