Lapco barrels have always been known for their performance. The Bigshot barrel is milled from a solid piece of aluminum, insuring the tightest tolerances possible. After milling, Lapco barrels are honed in three stages, insuring an internal finish that is smoother than glass. All this attention to the quality of the barrel, the finished Bigshot product is highly accurate and consistent. The Accushot Kit comes with three different barrel bores: .690, .687, .684