kls said:knock down power is what you want. If you want the badest semi you can get go for the 10mm 690 foot pounds of energy at 25 ft. can you say dead.
If you want force, throw a baseball at someone. A 100mph baseball has more force than virtually any handgun round. Hell, punch someone... a punch is more forceful than most rounds. Also, no gun shy of something on tracks or wheels is going to knock someone backwards like Hollywood would have you believe.