The use of water jugs and other back yard "ballistics media" tests and even ballistics gel prove NOTHING as nothing can replicate the human body's various tissues.
IMO those "experts" (especially the FBI) are perpetuating a fraud upon everybody thru their tests and the use of homogenous "ballistic gel". And here's my reasoning:
Every single defensive handgun bullet/load (with the exception of maybe Hornady's XTP) has been tweeked and redesigned, some even multiple times, by the manufacturer. These redesigns are to make said bullet more "effective". If a 1st Gen bullet design is just as effective on the streets as it is/was while being tested in the labs using the FBI's Protocols and ballistic gel, there would be absolutely NO reason to redesign their bullet(s).
I've seen redesigns of the Silvertip, Golden Saber, Gold Dots, several changes for the SXT (since it's original Black Talon design), numerous changes for the Hydra-Shok, and even some of the HST bullets has undergone a redesign and now I'm hearing that the Ranger Bonded/PDX1 is undergoing a change.
All this proves to me that the use of ballistic gel for testing does not reflect what said bullets are doing in real world shootings in real living human flesh, blood and bones. If every modern designed defensive handgun bullet worked in real world shootings, every single time, as well as they worked, every single time, in controlled, repeatable labratory test settings using ballistic gel, there would never be a need to modify and redesign those bullets. They would work perfectly in every shooting, wouldn't they? Unfortunately testing bullets in labs under controlled conditions doesn't reflect what happens in real world shootings out on the streets every single day.