I'm a certified Pepperball Instructor......
Basically they take a $100.00 Tippmann Rental Paintball gun, change a few things (like the logo) and sell it for $400.00.
There is different rounds too, there is a solid plastic for breaking glass (these could be lethal if you shot someone with them) Green "paint" ball that reacts to UV light. "Water" filled training and marking, "Practice" which is filled with baby powder to simulate the "pepper powder". These tools are chrono'd at 380 fps to guarantee breakage of the pepperball and some nice big welts......