I remember watching an episode of Myth Busters where they put a block of ballistic gel into a swimming pool and shot at it from everything between a Civil War pistol to a .50cal

Very cool to learn that the slow the FPS of the round, the further into the water it will penetrate.

Confirmed on the ballistic gel -- I initially thought it was ice.

> Watch for the hollow point rounds in the ballistics gel.

... from the YouTube summary.