I watched Harry Brown on DVD, which the great Michael Caine personally lifts from forgettable to above-average. It does though feature a common movie trope, namely that a bullet can thrown a grown adult across a room (Presuming a powerful enough gun).
Mass and Speed are roughly interchangeble forces in comic books and in many films. If a superhero who weighs 200 pounds wants to stop a hurtling train or bus that weighs many tons, it’s entirely a matter of having his feet planted correctly and a good set of biceps.
In college I read in Soldier of Fortune magazine that if a bullet — which not only has small mass but penetrates upon impact — can throw a human being backwards 3 or 4 feet, then a regular feature of baseball games would be batters landing in the upper deck after being beaned by a pitcher.
My personal favorite guy-flying-improbably-backwards comes at the conclusion (about 2:40 of the clip) of the gripping suspense film “Day of the Jackal” [SPOILER ALERT: this is the climax of the movie).