Dumbass appears for the first time along with his two Berettas. We see his point of view when the Pro shows him an acrobatic move involving jumping over a crate. Dumbass, being a...well, dumbass, attempts the move, but bashes himself up instead. Dumbass then proceeds to shoot the crate. This is when Dumbass notices Assassin, who fires at them, Dumbass attempts to save his teammate, but winds up getting him killed. Dumbass, in a fit of rage, kills Assassin.
The guns appear for the last time briefly in de_aztec, where Dumbass is introduced with them, the pistols are never seen again.