The Punisher features a secondary barrel that fires one armor-piercing round per main-barrel burst. It was developed by Blood Pack gunsmiths who found that their vorcha recruits frequently forgot to optimize ammo loads in the heat of combat. This configuration makes the process automatic and highly effective at penetrating armor.
As submachine guns go, the Punisher is rather heavy, so for power-dependent classes it is best used on its own or with the SMG Ultralight Materials mod if the player equips a second weapon.
While it has decent damage and a good rate of fire, the Punisher is inaccurate at long ranges. When using it, it is recommended to fire either up close to the enemy, or from cover where the crosshairs will reduce in size.
For Infiltrators, the Punisher serves as a solid backup for close range. The damage and rate of fire are comparable to an assault rifle, but with half the weight. This allows the player to equip a sniper rifle, Punisher, and even a heavy pistol, all while maintaining a bonus to their power recharge speed. Further, combined with Disruptor Ammo, it's more efficient to shred heavy targets such as Geth Primes or Cerberus Atlases with a Punisher than to use a Mantis at distance, especially in tight quarters where the reload time of a rifle gives the enemy the opportunity to close in. The same can be true using Warp or Armor-Piercing Ammo for Brutes and especially Banshees.
For those who wish to use the gun at longer ranges or want to shoot more accurately, the scope is recommended. While the gun scoped in does have a high vertical climb, this can be controlled by moving the reticule down while shooting or burst firing. Shooting from cover will help reduce vertical climb.
Adding the SMG High-Velocity Barrel from Leviathan allows the Punisher to literally be a power-based class's only weapon, melting through even Atlases with ease.
The Punisher is highly effective with Marksman when you evolve the power for accuracy and duration.
Sustained shooting will trigger the armor-piercing round to fire every 8 rounds. The special round is represented by a backfire effect and a sudden jolt in the weapon's aim. This will not happen if the trigger is not held for a full 8-round 'burst'.
When combined with the damage boosts given by both Warp and Proximity Mine on the same target, the Punisher can eat through armored targets at close range with frightening speed, even dropping a full stat Brute with the second armor-piercing shot on Insanity. Banshees reduced to armor on Insanity with this tactic are killed with the third AP shot.