If you're looking for a squib, they are explosive, and carry a multitude of risks. Check out ?url? http://www.exposure.co.uk/eejit/blood/index.html?/url?
That's a low budget, safer alternative.

"We all have the potential to be great. It is our inability to do so that makes us miserable." C.S.Lewis

That's excellent. Many thanks to you, kind sir.

___________________________________
You can't keep 'em out, they're already in!

Interesting. Where can one purchase these 'squibs'

A squib is a small explosive device used for triggering a larger explosion, or (by itself) its
own explosion. They range in size from a millimeter (to shatter a bottle, for example) to
15 or so millimeters (for a blood bag) and are ignited by an electric current. Since a squib
is an explosive device you need a license to purchase, transport and use them.
A little trick I?ve used:

Thread a length of fishing line 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 line 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.

Another method uses tubing and some method of air pressure. Aquarium tubing is
essential. Attach one end to a small hole cut in the costume and the other to a syringe
or sprayer for great bloodletting.

You can use a large syringe - 100cc and bigger. Check ?URL="http://www.burmanfoam.com/"?Burman Industries?/URL? or any medical supply store.

Smaller syringes - 50cc or so - are great for a good bullet hit. The bigger ones
are good for a neck cut or even a severed hand or arm. With a little practice you
can get a nice blood pumping effect.

Use a ?url="http://www.hdhudson.com/"?Hudson Sprayer?/url? for longer sprays
like in Japanese martial arts and Samurai movies.

Years ago I found two water fire extinguishers at a thrift store. You can unscrew
the top, fill it with your blood mixture and then pressurize it at a gas station air
pump. Huge, long, powerful sprays of blood for an over the top horror movie.

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

iv made a few war films and i have come to dislike the use of fake blood. simply because after loads of people have been shot and every one is covered in stickey slimey fake bloody which stops all duct tape for sticking (making it extrememly hard to stick a tube in place under an actors clothing)and it will get EVERYWHERE. in band of brothers, most of the time when soldiers get shot you dont see blood, you just see white dust/powder come out. so i get a small banger (half the size of your pinkey finger), elelctrically connect it to a car battery for timed detonation. place it in a small plastic bag (the small clear ones ) filled with red powdered paint and place under actors clothing via tape or whatever, pre cut hole and when detonated it will explode the bag, sending red powder flying out the hole looking like the spray of blood, and much more cleaner and practical. this takes a lot of practice to perfect, and i live in uk so bangers are hard to get hold of.

whats good is to use

http://www.exposure.co.uk/eejit/blood/index.html

but i find it to be quite a 'feeble' looking bullet wound. so then in post you can layer a bigger squib hit, with lots of dust flying out, on top of it. using real, on set footage combines with greenscreen effects works really well as you retain the realistic look and a cool/shocking/impressive look at the same time. if that made any sense!

Problem with the hand sprayer thing. At least where I live on the East Coast USA, it seems impossible to get a hand sprayer like they have. The pump sprayers here have nozzles either like this:
Or like this:

Not like the one in the example.

What I mean is that in their example from exposure.co.uk/eejit/blood/index.html is that their sprayer has the handle before the tubing. By having the handle with attached nozzle after the tubing such as in the sprayers I linked, you can't do the effect they are showing. So you'd need a different kind of sprayer, which I can't seem to find.

The majority of the time, professional Special Effects Makeup Artists will use a simple large syringe and rubber tubing to "spurt" blood from wherever it is supposed to spurt from. If the effect needs to be more powerful than the syringe can provide, an air-compressor system may be used.

Below is a list of some of the popular Makeup and Special Effects Makeup books available that may help you with this effect and more! And for more information about filmmaking in general and how to build an actual career in Makeup in the industry, visit http://www.whatireallywanttodo.com.

Good luck!

Make-Up and Costume for Television (Media Manuals) (Media Manuals) (Paperback)
by Jan Musgrove (Author)
Product Details
Paperback: 208 pages
Publisher: Focal Press; 1 edition ( July 18, 2003 )
Language: English
ISBN-10: 0240516605
ISBN-13: 978-0240516608
?
The Technique of the Professional Make-Up Artist (Paperback)
by Vincent Kehoe (Author)
Product Details
Paperback: 290 pages
Publisher: Focal Press; 1 edition (July 17, 1995)
Language: English
ISBN-10: 0240802179
ISBN-13: 978-0240802176
?
Special Make-Up Effects (Paperback)
by Vincent Kehoe (Author)
Product Details
Paperback: 144 pages
Publisher: Focal Press (January 8, 1991)
Language: English
ISBN-10: 0240800990
ISBN-13: 978-0240800998
?
Stage Makeup: The Actor's Complete Guide to Today's Techniques and Materials (Paperback)
by Laura Thudium (Author)
Product Details
Paperback: 160 pages
Publisher: Back Stage Books (April 1, 1999)
Language: English
ISBN-10: 0823088391
ISBN-13: 978-0823088393
?
Special Effects Make-Up (Paperback)
by Janus Vinther (Author)
Product Details
Paperback: 256 pages
Publisher: Theatre Arts Book; 1 edition ( October 9, 2003 )
Language: English
ISBN-10: 087830178X
ISBN-13: 978-0878301782
?
A Complete Guide to Special Effects Makeup: Conceptual Artwork by Japanese Makeup Artists (Paperback)
by Graphic-Sha (Author)
Product Details
Paperback: 136 pages
Publisher: Graphic-Sha ( December 15, 2007 )
Language: English
ISBN-10: 4766118332
ISBN-13: 978-4766118339

Brian Dzyak
Cameraman/Author
IATSE Local 600, SOC
http://www.whatireallywanttodo.com