Welcome to filmmaning.net, deadman.

Poke around the site a bit and you'll find some great links and answers. For example:
?url? http://www.filmmaking.net/faq/answers/faq41.asp?/url?

I'm a licensed pryo technition. I recomment the compressed air method if you cannot afford a pro on the set. Explosives can and do hurt people. Also, using even a small charge can be illegal, depending on where you live.

A little trick I?ve used:

Thread a length of fishing wire through a small button with a needle. Carefully punch the needle through the inside of a condom so the button is inside. A drop of latex will seal the tiny hole the needle made.

Fill the condom with blood and seal it.

Attach the condom to a heavy (but small) piece of cardboard with super glue or liquid latex. With a bit of twine, tie this cardboard backing to your actor.

Now score the costume where you want the blood to fly. Thread the fishing wire through the costume and set up your shot. When you yank hard on the fishing line, the button will pull out of the condom and the blood will spray.

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The aim of an argument or discussion should not be victory, but progress.
Joseph Joubert, essayist (1754-1824)

They used a similar trick to that mentioned by Certifiied Investigator while filming the original Dawn of the Dead.

Fill condom with blood. Attach tube to one end. Hide condom under wig and use makeup to hide tube. End of tube should be a small button covered in makeup. Connect fishing line to the button. When target is shot yank the fishing line to pull the button off and allow blood from condom to flow out onto target's face. Even in slow motion knowing it's happening it's hard to tell the button is a button, it looks a bit like a chunk of flesh from the shot because of makeup and such still attached when it's yanked off.

RJSchwarz
San Diego, CA