eli5 Why do militaries use depleted uranium in armor and ammunition

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It has properties that make it ideal for military usage, both defensively and offensively. It’s also cheap and readily available. **Density**- DU is very dense, which means it can absorb a lot of energy, like from the impact of an incoming projectile when used in armor plating. Conversely, as a projectile it can *carry* a lot of energy- meaning it can be highly destructive for its size when placed into the core of a conventional bullet or projectile. **Anti-Tank Weapons**- A big challenge on the battlefield is neutralizing enemy armor, such as tanks. Not only do you need a projectile that will penetrate its thick armor, but you also need to disable it- such as by killing the crew inside. A DU projectile can do both of those things because it has two very appealing properties- it fractures on impact into razor sharp pieces and it readily ignites into ferocious flames when it does. So with DU you have a high energy projectile that punches through armor plating, breaks into a swarm of deadly sharp spikes, and then incinerates the crew inside in a molten fireball. That makes it exceptionally appealing considering those rounds can be fired from a man-portable weapon.


It’s really heavy. That’s all there really is to it. There’s a limit to how fast you can get bullets going, and the how-hard-it-hits factor is determined by speed times mass. So you want the heaviest (ie, densest, because there are also limitations on size) projectile possible. That’s uranium. Pretty much everything else that people will tell you about uranium isn’t really about how *uranium is great at this* as much as how *uranium doesn’t suck at this as much as you might have though, considering we only picked it because it was super-heavy.*


It is as dense and heavy as metals can get. You want that in the core of bullet because more density/mass = more energy which, in turn = better armor-piercing capability. DU also tends to break apart into deadly shrapnel rather than mushrooming like other metals do. That can be devastating to the people inside the target.


It is very dense and it is really cheap to get since it’s both found in nature and a byproduct of nuclear energy/production processes. The isotope that is used, U-235, only emits alpha particles so it’s not *too* dangerous as long as you’re not licking it or eating it. Alpha particles can be “stopped” by putting a few feet of distance between you and the radioactive source, or using virtually any kind of material (from paper to lead or anything in between) to create a shield.


Depleted Uranium is very dense. It’s denser that tungsten so it does a better job of being heavy and still fitting into a cannon barrel.