In all seriousness, Karl is a cool guy and he's got a good sense of humor. This is epic trolling right here, that's what that is.
In case you aren't familiar with InRangeTV, they perform a lot of mud tests on guns. The joke is about a gun getting the bucket/hose if it won't function properly, a play on the scene from Silence of the Lambs.
It's actually a catchy song once you get over the association with Ted Levine's disturbing tuck scene in the film.
Clayton E. Cramer
Gun Free Zone
The War on Guns
The View From Out West