M2 50 Caliber Machine Gun
Near the end of the movie, the dinosaur faces the fire of a 50 caliber machine and shrugs it off. Wrong! The M2 machine gun, which fires a bullet half an inch in diameter, would be capable of killing a T Rex or any other animal that ever lived. A T Rex masses about 6 tons, the same as a modern elephant, except the T Rex has a rangier build, which means its vital organs are not buried so deep in its body as an elephant. Now you can kill an African bull elephant with one or two shots from a shoulder fired rifle, the so-called elephant gun. The M2 amounts to a pintle mounted, crew served, fully automatic elephant gun with a longer barrel and faster muzzle velocity and a bullet just as heavy. With an elephant gun, you pull the trigger and get one or two shots. With the M2, you depress the butterfly trigger and get one or two dozen shots. Hold it down longer and you get one or two hundred shots.
The chances that a T Rex or any other animal could survive a close encounter with a 50 cal are zero.