In a survival situation I don’t think that any caliber comes close to the versatility of a .22LR. In the movie, it looks like the pistol being fired is a .38 special. I just weighed a 158g .38 special on my triple-beam scale and it weighed 15.3 grams. For the same weight, you can carry 5 CCI .22LR HP 36g. cartridges.