buck shot effect can it be done?

would i need mulipul barels and multipul pistons or how whould this work out?

You can have one plunger leading to multiple barrels, multiple plungers to individual barrels, shove a few darts down the one barrel but your best bet is to get an air-tanked blaster connected to multiple barrels. I forget what it's called but there is something specifically named for this. Maybe someone else can help you out more.

thanks i looked into it from what i saw it seems that they have air tubes from the plunger tube connecting to the multiple barels and all that air pressure is released into X number of barels if im correct

Your best option for shotgun stuff would be an airblaster (like the BuzzBee Ultimate Missile Blast) and an absolver.

Check out this link for ideas on how to make an absolver. Then you just need to modify to suit the available materials in the states and you're done.