SpudFiles

what is a burst disc? I did a search, but i cant find out what they are.

they are a thin sheet of material put inbetween the barrel and the chamber, used as a noisemaker, in a hybrid, and as a real simple pnuematic.
common materials are tinfoil, tape, and plastic from soda bottles

just realized they are explained in the wiki here:
http://www.spudfiles.com/spud_wiki/index.php/Burst_disk

they take the place of a valve, they are placed in a union between barrel and chamber, when the pressure is high enough it bursts, giving a high fast flow of air, they are usually something like aluminum foil, milk jug plastic, trash bag plastic, somewhere along the lines of that
Edit:darn it, I get beat to the answer every time

Oh, so they're kinda like a valve that u can use instead of a sprinkler or a ball?..and how do u get the burst disc in there?

you have some kind of a union, like a breech loader

what do u reccomend for my 1st pneumatic, a sprinkler valve, or burst discs?

A burstdisk is very reliable and will have much better flow (and thus better preformance) than a sprinkler. It's also cheaper and more available (just about every hardware store, compared to very few hardware stores).
With a triggered burst disk system (outlined in our wiki) you can chose when the burst disk ruptures. (although such a system will bring the cost of the system up to near that of sprinkler)

This means that the benifit of a sprinkler valve is increasing the rate of fire; you don't have to open 1 or even 2 unions, remove the ruptured disks, insert new ones, and close it back up... and you don't have to cut the ruptured disks out either.

thanks for all the info guys