0 ▁gauge . ▁The ▁military ▁version ▁ 7 7 E ▁was ▁the ▁most ▁widely ▁used ▁shot gun ▁of ▁the ▁Vietnam ▁War . ▁It ▁was ▁a ▁short - bar re led ▁p ump - action ▁shot gun ▁known ▁various ly ▁as ▁the ▁" tr en ch " ▁or ▁" ri ot " ▁shot gun ▁in ▁ 1 2 ▁gauge . ▁The ▁Military ▁Model ▁ 7 7 E ▁had ▁a ▁notice ably ▁shorter ▁stock s ▁than ▁similar ▁United ▁States ▁military ▁shot g uns ▁built ▁by ▁I th aca ▁Gun ▁Company , ▁Rem ington ▁Ar ms , ▁and ▁Win chester ▁Re pe ating ▁Ar ms ▁Company . ▁These ▁short ▁stock s ▁were ▁intended ▁to ▁accommod ate ▁South ▁Vietnam ese ▁soldiers , ▁and ▁the ▁Military ▁Model ▁ 7 7 E ▁was ▁the ▁first ▁United ▁States ▁combat ▁shot gun ▁equ ipped ▁with ▁a ▁rub ber ▁re co il ▁pad . ▁Military ▁Model ▁ 7 7 E ▁shot g uns ▁were ▁Parker ized ▁with ▁s ling ▁sw iv els ▁and ▁wooden ▁stock s . ▁Rece ivers ▁were ▁marked ▁" U . S ." ▁and ▁" p " ▁proof marks ▁appeared ▁on ▁both ▁bar rel s ▁and ▁rece ivers . ▁ ▁A ▁few ▁pro tot ypes ▁were ▁fitted ▁with ▁bay on et ▁ad ap ters , ▁but ▁none ▁are ▁known ▁to ▁have ▁been ▁issued . ▁A ▁few ▁Stevens ▁Model ▁ 6 9 R ▁shot g uns ▁also ▁saw ▁service ▁during ▁the ▁Vietnam ▁War . ▁The ▁Model ▁ 7 7 E ▁gave ▁satisf actory ▁service , ▁but ▁proved ▁less ▁dur able