Which component of a shotgun is located at the forefront of the firearm?

The component located at the forefront of a shotgun is the forend or forestock. This part serves a crucial role in operating the shotgun; it allows the shooter to stabilize and control the firearm during firing. The forestock is typically grasped with the non-dominant hand while aiming and shooting, providing leverage and helping to manage recoil.

In contrast, the rear stock is situated at the back of the shotgun, supporting the shooter's shoulder. The action bar relates to the mechanism that operates the loading and ejection of shells, but it is not positioned at the forefront. The trigger guard is important for safety as it protects the trigger from accidental engagement, but it also does not occupy the front part of the shotgun. Thus, the forestock is undeniably the correct answer as it represents the foremost component that plays a critical role in the handling of the firearm.