At the beginning of Terminator 3: Rise of the Machines
(Arnold Schwarzenegger, 2003) there's brief mention of a paintball gun,
but it turns out to be what is probably an Airsoft replica of a Walther PPK.
After breaking in to the animal clinic, John Connor (Nick Stahl) tries to stop Kate (Claire Danes) from calling the police,
by threatening her with the PPK.
Kate distracts the woozy John, and takes the gun from him.
Kate them presumably recognizes it as not a real firearm (or may have
known beforehand) and shoots John twice, supposedly with paintballs.
John, locked in a dog cage, shows us the splats of paint on his hands. Even if the gun was an airsoft firing paintballs,
the splats of paint are far too large to have come from 6mm paint rounds.