Shooting Watermelons with 'Exploding' Sodium Bullets!
Why Worldbuilding Stack Exchange recommends it
Worldbuilding Stack Exchange answerers point people to it as real footage of reactive-metal bullets when writing about explosive ammunition, pyrophoric liquids and weapons that blow up soft, wet targets.
Recommended by 2 people across 2 different months, 2016 to 2021.
What it is
TheBackyardScientist fires modified .45 hollowpoint bullets loaded with sodium, potassium and a liquid sodium-potassium alloy (NaK) into watermelons, cinderblocks and starting fluid. It is part two of a liquid metal bullet experiment, filmed as an informal backyard demonstration.
What people said
Recommends MolbOrg · 2016-09 · Worldbuilding Stack Exchange · on “Potential of Potassium/Caesium Bullets?”
this video probably should answer your question completely Shooting Watermelons with 'Exploding' Sodium Bullets! [this video]
Recommends Willk · 2019-12 · Worldbuilding Stack Exchange · on “if there was a dragon that spits pyrophoric liquids like a spitting cobra”
The pyrophoric liquid could be NaK: sodium potassium liquid metal. [LINK] The alloy of sodium and potassium forms a very lightweight liquid metal. Depicted is an electromagnetic fountain of this liquid metal, from the Periodic Videos series. From that video: “It’s so reactive that it will react with the water in the air and it will be on fire before it even reaches the water. It is a liquid and therefore the surface is clean so the oxygen and water in the air can get to the surface much better than it could as a solid.” -Professor Martyn Poliakoff. NaK explodes into flames in water, and also in air. The Backyard Scientist filled bullets with the stuff. These bullets acted like tracer bullets
Cites Willk · 2019-12 · Worldbuilding Stack Exchange · on “A bullet that makes the target explode”
Backyard Scientist filled bullets with sodium potassium alloy, and those things blew up a watermelon very well. Fire and everything. [this video] [LINK] That smoke trail was left by the bullet in the air. Cool stuff! I suspect these NaK bullet would only blow up things that were soft and wet. Water is what makes NaK explode, and these bullets had barely any penetrating power - they are soft and light. Hopefully you are interested in blowing up watermelons and other large fruits. Durian, maybe.
Cites Nosajimiki · 2020-10 · Worldbuilding Stack Exchange · on “What single or two materials are suitable to fit inside of a glass bullet to make it explode on impact?”
You don't use explosive bullets to overcome armor You can make explosive bullets quite easily, Sodium/Potassium bullets are a really good example that can be quite devastating against soft tissue... but that is not what you are asking. As you can see in this video [this video] , they can make a watermelon explode quite spectacularly, but when it comes to penetration, they have less penetrating power than a normal lead bullet. If you want to make an explosive penetrate more than a lead bullet, you need to fire a shape-charged [LINK] bullet such that it is able to explode into an energetic spray with an even smaller radius than your slug, but doing this at the scale of personal firearms is incredib
Cites Nosajimiki · 2021-04 · Worldbuilding Stack Exchange · on “What do my wizards drop on towns to turn them into craters?”
Sodium Sodium is a basic element that can be using for making bullets that explode violently on impact [this video] . Because it is a pure element, it's composition could not be any simpler. I can't find any exact calculations, but if a simple handgun bullet can contain enough sodium to make things explode this dramatically, I'd imagine dropping a 100 ton ball of the stuff would produce a very impressive crater. Apart from being highly explosive, this solution is good because the fallout would quickly react with various elements in the ground forming common salts. While your target zone may be rendered agriculturally ruined for a few decades, it would not be so toxic as to be a threat to people s