Repeating Arrow Trap
Start out making a five long row of dispensers.
Redstone
Place the Redstone along the dispensers put repeaters facing the dispensers make a circle of repeaters set them to tick 4
Firing
this is what you will see with the arowes mid fire
Done
With the arowes fired and disappeared or you colectied them you will need to reset the trap
Grouped
This is when you will go in and colect the arowes and the loot