TriStar 24117 Viper G2 16 Gauge 28" 5+1 3" Black Rec/Barrel Semi-Gloss Turkish Walnut Stock Right Hand (Full Size) Includes 3 MobilChoke. The TriStar Viper series is a semi-automatic, gas operated shotgun that is reliable, functional and hard working. Its removable choke system uses Beretta/Benelli Mobil threads, includes three choke tubes (IC, M, F), choke box, and wrench. The Viper also features manual E-Z load mag cut-off, vent ribbed barrel with matted sight plane & fiber optic front sight and chrome-plated chamber. A shot plug is included. This 16 gauge G2 model features a black finish and walnut stock.