The Double-Barrel Shotgun is a Small Gun in Fallout: Brotherhood of Steel.
With its twin barrels of justice, this rifle fires a decent-sized spray of pellets at an oncoming enemy.
A shotgun, also called a "scattergun", is a firearm designed to shoot a multitude of projectiles with a single pull of the trigger. This makes it very effective at hunting game, greatly increasing the weapon's hit potential. However, the accuracy and power found at close range diminish rapidly as you get farther away from the target. Shotguns designed for military use are often called "combat shotguns".
It's really powerful weapon through much of the game, especially with anyone with high Critical Chance, but it uses far too much ammunition.