Which of the following describes the barrel of a shotgun used for shotshells?

The barrel of a shotgun used for shotshells is best described as a smoothbore barrel without rifling. This design is intentional, as shotguns use shotshells that contain multiple small pellets (shot) rather than a single bullet. A smoothbore barrel allows the shot to spread out after being fired, which increases the likelihood of hitting a target at close range.

The absence of rifling—spirals cut into the inside of a barrel to impart spin to a bullet—enables the fatal spread of the shot, making it effective for hunting birds and small game, or for self-defense situations. The consistency in the bore size and the smooth surfaces help maintain the integrity of the shotshells as they travel down the barrel.

Options suggesting a bull barrel with grooves or a rifled barrel with a scope would indicate firearms designed for precision shooting with single projectiles, which is not characteristic of typical shotgun usage. While some shotguns can have adjustable components for slugs or specific bullet types, the standard for the barrel used with shotshells remains the smoothbore design.