Buy a nerf gun and Modify it for Office Warefare.
The original Nerf Gun Longstrike
Open it up to access its internals
Add a Gasket or Rubber Ring or Plastic Ring here. Compress the spring by 0.25-0.35 inch.
The ring close up, and stretch the spring a bit. Results 10-20 feet original to 30-35 feet modded.
Drill the anoying air restrictor out, dont drill too big of a hole. adds another 10-15 feet range.
Modify the clip so the rear Stock can be removed but yet stays in solid if prefered.
SUper Glue these damn srpings to the button so i dont loose them.
GO TO WORK AND SHOOT UR CO WORKERS !!! LET THE WAR BEGIN !!!