Here is a cool piece of movie trivia. Dad was reading "How in the World? A Fascinating Journey Through the World of Human Ingenuity", a really cool book about a wide variety of questions that people ask/wonder about science, inventions, food, special effects, etc. Have you ever watched a movie where something/someone gets shot and you wonder how they make the bullet holes? Being great fans of westerns, my sister and I have tried to figure it out many times. Here is a very interesting, concise explanation.
"In the early days [of movies], bullets hitting walls, bottles or fences were actually fired by a marksman using live ammunition. But it was potentially dangerous and other techniques had to be developed.
For bullets splintering a wooden wall, detonator caps of gunpowder were inserted and eploded to synchronize with the gunshot. For bullet hits on people, a similar cap was attached to a metal plate that the actor wore under his clothing. The cap was electrically detonated by wires leading to a technician's "keybourd". But it could result in burns or lacerations from fragments.
So effects men developed the "squib" - a small, smokeless, non-metallic, explosive charge. It can be detonated by small batteries strapped to the actor, by wires from a control board, or by radio control.
For her "death" in Bonnie and Clyde (1967), Faye Dunaway had scores of squibs concealed beneath her clothing. The effects man Danny Lee arranged them in sequences, and they were wired to an off-camera battery which detonated them in sequences. The car in which Bonnie was machine-gunned was first punched with holes into which squibs were inserted and then painted over. The scene was shot at high speed which, played back normally, gave the shot a slow, dreamlike quality."
Now that you know how the shots are created, what about when there's blood? Easy . . .
"The effects man. . . attached latex bags to the squibs. The bags were filled with bright red, gelatine-based fluid. When the squibs burst the bags, the "blood" spurts."
"To create the effect of a pear, arrow or knife striking someone, the most common technique is to fire the projectile, which is hollow, along a wire from a compressed air device. The wire is attached to a metal plate strapped under the actor's clothing. The spear speeds along the wire and thuds into a cork pad fixed to the plate."
Well, how is that for ingenuity! Next time you see a rousing gun battle you can explain how it happens!