This one’s bugged me for a while. I can clearly remember the print ads and I’d swear the movie’s title was “Combat Football.” The cutline was something like “At the two-minute warning… they give the quarterback a rifle.” The image was a grainy sports-action shot of, well, a QB holding a rifle. That led me to think it might have been “Two Minute Warning,” but that’s a different football-stadium-with-a-rifleman flick.
Norman Spinrad wrote a short story titled The National Pastime about the invention of Combat Football. Played in the summer, players wore only shorts and shoes, no protective gear and literally no holds barred in tackling, blocking or beating the living daylights out of the other players.