In case you didn’t already know Group I metals like Potassium and Sodium react violently when introduced to water.
With that being said what happens when you fill the end of a hollow point bullet with one of these reactive metals? The video bellow shows you all of those explosive details in slow motion. As the tester found out, these exotic rounds have a devastating effect on his “Fish Tank”. If you look closely at the high speed footage you can actually see the combustion products from the metals igniting under water. While these rounds did not perform significantly better than traditional jacketed lead bullets they did have some very unique properties.
Ultimately these rounds are just science experiment and they have almost no real world application.