In the wake of the tragic “Dark Knight Rises” shootings in Colorado, Warner Bros. has reportedly been discussing moving the release date of its film “Gangster Squad” — which includes a scene of 1940s mobsters opening fire on a movie theater through the back of a cinema’s screen. There’s also talk the studio may minimize the scene by recutting the film, which was scheduled to come out Sept. 7. Meanwhile, Hollywood has a slew of upcoming gun-heavy films due this summer, including the “Total Recall” remake and “The Bourne Legacy.”