The film
Hollow Man (Kevin Bacon, 2000) prominently features paintball guns used as tranquilizer dart guns.
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Frank Chase (Joey Slotnik) picks up several Benjamin-Sheridan
PGP pistols, fitted as tranquilizer dart guns, to hand out to the rest of the crew.
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Janice (Mary Randle) says "she's in" if it comes down to shooting Caine (Kevin Bacon.)
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Linda (Elizabeth Shue) prepares to fire her PGP, thinking Caine is hiding in the locker.
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Carter (Greg Grunberg) shows us how to load a tranquilizer dart into
the (modified) top tube of his PGP. Note the sliding "loading slot"
cover.
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Carter and Matthew (Josh Brolin) try and corner Caine in the access
tunnels. The PGPs appear completely unmodified except for the top tube.