Watch these bros fire bullets from a WWI-inspired device in slow-motion

Gavin Free and Daniel Gruchy (aka  The Slo Mo Guys) have taken their Streamy Award-winning science and technology web series to the Nevada desert.
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This time, they're filming (in slow-motion, of course) bullets shot from a contraption that attempts to recreate a WWI-era propeller plane.
Gruchy explains, "As a kid I never understood how they managed to do the thing where they fired machine guns through the pro