This weapon is also called the Helsing within the game.
You must make 30 kills (human, mutant or animal/beast) with this weapon for the achievement to unlock.
You can save and load when you kill enemies and they will count for the achievement progress.
Grips: Light Grip and Forend; Assault Stock, Grip and Forend; Sniper Stock, Grip and Forend; Heavy Stock
Bows: Recurve Bow, Compound Bow, Twin Bow, Pneumatic Bow System
Compound increases damage, but not as much as Twin Bow.
Pneumatic Bow transforms Helsing into something akin to the firing speed of the Revolver, except with retrievable or explosive bolts.
Sights: Iron Sights, Reflex Sight, NV Scope, Scope 4X
The Helsing is excellent at anything between extremely close and extremely far.
Magazine: Small Magazine, Medium Magazine, High Capacity Magazine
1 bolt, 3 bolt and 8 bolt magazines.
Gadgets: Red Laser, Infrared Laser