# Is depleted uranium at all useful for defeating body armor?
**URL:** https://boards.straightdope.com/t/is-depleted-uranium-at-all-useful-for-defeating-body-armor/1023168
**Category:** Factual Questions
**Created:** [September 18, 2025, 9:06pm UTC](https://boards.straightdope.com/t/is-depleted-uranium-at-all-useful-for-defeating-body-armor/1023168 "2025-09-18T21:06:35Z")
**Posts on this page:** 19
**Page:** 1
### Author:  [@Lumpy](https://boards.straightdope.com/u/Lumpy)
#### Post date: [September 18, 2025, 9:06pm UTC](https://boards.straightdope.com/t/is-depleted-uranium-at-all-useful-for-defeating-body-armor/1023168/1 "2025-09-18T21:06:35Z")
Since the introduction of practical, militarily significant infantry body armor, armaments manufacturers have been working to defeat it. Submachine guns firing pistol rounds have been displaced by Personal Defense Weapon calibers, and the fairly light assault rifle rounds like 5.56×45mm and 5.45×39mm are being phased out in favor of harder-hitting projectiles in the 6mm range. Given the glowing reports of the near-magical effectiveness of depleted uranium projectiles, is this being at all considered for rifle rounds intended to defeat body armor? Is it a matter of cost or is DU more problematic than at first glance?
---
### Author:  [@kenobi\_65](https://boards.straightdope.com/u/kenobi_65)
#### Post date: [September 18, 2025, 9:09pm UTC](https://boards.straightdope.com/t/is-depleted-uranium-at-all-useful-for-defeating-body-armor/1023168/2 "2025-09-18T21:09:48Z")
Well, the stuff is apparently pretty toxic:
> [@](#):
>
> The use of DU in [munitions](https://en.wikipedia.org/wiki/Munitions) is controversial because of concerns about potential long-term health effects.[[3]](https://en.wikipedia.org/wiki/Depleted_uranium#cite_note-Miller-3)[[4]](https://en.wikipedia.org/wiki/Depleted_uranium#cite_note-Pattison-4) Normal functioning of the [kidney](https://en.wikipedia.org/wiki/Kidney), [brain](https://en.wikipedia.org/wiki/Human_brain), [liver](https://en.wikipedia.org/wiki/Liver), [heart](https://en.wikipedia.org/wiki/Human_heart), and numerous other systems can be affected by exposure to uranium, a [toxic metal](https://en.wikipedia.org/wiki/Metal_toxicity).[[5]](https://en.wikipedia.org/wiki/Depleted_uranium#cite_note-Craft-5) It is only weakly [radioactive](https://en.wikipedia.org/wiki/Radioactive) because of the long [radioactive half-life](https://en.wikipedia.org/wiki/Half-life) of 238U (4.468 billion years) and the low amounts of 234U (half-life about 246,000 years) and 235U (half-life 700 million years). The [biological half-life](https://en.wikipedia.org/wiki/Biological_half-life) (the average time it takes for the human body to eliminate half the amount in the body) for uranium is about 15 days.[[6]](https://en.wikipedia.org/wiki/Depleted_uranium#cite_note-6) The [aerosol](https://en.wikipedia.org/wiki/Aerosol) or [spallation](https://en.wikipedia.org/wiki/Spallation) [frangible](https://en.wikipedia.org/wiki/Frangible) powder produced by impact and combustion of depleted uranium munitions (or armour) can potentially contaminate wide areas around the impact sites, leading to possible inhalation by human beings.[[7]](https://en.wikipedia.org/wiki/Depleted_uranium#cite_note-Mitsakou-7)
>
> The actual level of [acute](https://en.wikipedia.org/wiki/Acute_toxicity) and [chronic toxicity](https://en.wikipedia.org/wiki/Chronic_toxicity) of DU is also controversial. Several studies using [cultured cells](https://en.wikipedia.org/wiki/Tissue_culture) and laboratory [rodents](https://en.wikipedia.org/wiki/Rodents) suggest the possibility of [leukemogenic](https://en.wikipedia.org/wiki/Leukemia), [genetic](https://en.wikipedia.org/wiki/Gene), [reproductive](https://en.wikipedia.org/wiki/Reproduction), and [neurological](https://en.wikipedia.org/wiki/Neurological) effects from chronic exposure.[[3]](https://en.wikipedia.org/wiki/Depleted_uranium#cite_note-Miller-3) According to [Al Jazeera](https://en.wikipedia.org/wiki/Al_Jazeera_Media_Network), DU from American artillery is suspected to be one of the major causes of an increase in the general mortality rate in Iraq since 1991.[[8]](https://en.wikipedia.org/wiki/Depleted_uranium#cite_note-jaz1-8) A 2005 [epidemiology](https://en.wikipedia.org/wiki/Epidemiology) review concluded “In aggregate the human epidemiological evidence is consistent with increased risk of birth defects in offspring of persons exposed to DU.”
> **[Depleted uranium](https://en.wikipedia.org/wiki/Depleted_uranium)**
>
> Depleted uranium (DU), also referred to in the past as Q-metal, depletalloy, or D-38, is uranium with a lower content of the fissile isotope 235U than natural uranium. The less radioactive and non-fissile 238U is the main component of depleted uranium.
> Uranium is notable for the extremely high density of its metallic form: at 19.1 grams per cubic centimetre (0.69 lb/cu in), uranium is 68.4% more dense than lead. Because depleted uranium has nearly the same density as natural uranium but far le...
---
### Author:  [@crowmanyclouds](https://boards.straightdope.com/u/crowmanyclouds)
#### Post date: [September 18, 2025, 9:24pm UTC](https://boards.straightdope.com/t/is-depleted-uranium-at-all-useful-for-defeating-body-armor/1023168/3 "2025-09-18T21:24:26Z")
> **[Saboted light armor penetrator](https://en.wikipedia.org/wiki/Saboted_light_armor_penetrator)**
>
> The saboted light armor penetrator (SLAP) family of firearm ammunition is designed to penetrate armor more efficiently than standard armor-piercing ammunition. In the US it was developed by the Marine Corps during the mid/late 1980s and was approved for service use in 1990 during Operation Desert Storm. It uses a reduced caliber, heavy metal (tungsten) .30 inch diameter penetrator wrapped in a plastic sabot of .50 inch diameter, and the .308 SLAP round was a .223 inch diameter penetrator core wit...
To put it in other terms, a fist will not penetrate body armor but the same amount of force with an ice pick will.
---
### Author:  [@Stranger\_On\_A\_Train](https://boards.straightdope.com/u/Stranger_On_A_Train)
#### Post date: [September 18, 2025, 9:27pm UTC](https://boards.straightdope.com/t/is-depleted-uranium-at-all-useful-for-defeating-body-armor/1023168/4 "2025-09-18T21:27:14Z")
Additionally:
> **[Depleted Uranium | IAEA](https://www.iaea.org/topics/spent-fuel-management/depleted-uranium)**
>
> Uranium (chemical symbol U) is a naturally occurring radioactive element. In its pure form it is a silver-coloured heavy metal, similar to lead, cadmium and tungsten. Like tungsten it is very dense, about 19 grams per cubic centimetre, 70% more dense...
> **[402-r-06-011\_508-d\_0.pdf](https://www.epa.gov/system/files/documents/2025-02/402-r-06-011_508-d_0.pdf)**
>
> 718.04 KB
> **[Depleted uranium](https://www.who.int/teams/environment-climate-change-and-health/radiation-and-health/environmental-exposure/depleted-uranium)**
>
> Depleted uranium (DU) is a byproduct of the uranium enrichment process used in nuclear power plants and weapons production. It is a dense, heavy metal with unique properties that make it useful in military applications, such as armor-piercing...
Stranger
---
### Author:  [@Lumpy](https://boards.straightdope.com/u/Lumpy)
#### Post date: [September 18, 2025, 9:30pm UTC](https://boards.straightdope.com/t/is-depleted-uranium-at-all-useful-for-defeating-body-armor/1023168/5 "2025-09-18T21:30:23Z")
I was wondering if the supply of DU is limited by the amount of uranium enrichment serving the nuclear industry, that there simply wouldn’t be enough for billions of small-arms rounds.
---
### Author:  [@HMS\_Irruncible](https://boards.straightdope.com/u/HMS_Irruncible)
#### Post date: [September 18, 2025, 9:38pm UTC](https://boards.straightdope.com/t/is-depleted-uranium-at-all-useful-for-defeating-body-armor/1023168/6 "2025-09-18T21:38:33Z")
The main benefit of DU rounds is how much kinetic energy they can deliver. So it wouldn’t be enough just to make DU bullets, there would need to be more propellant, which would require a sturdier barrel, and all sorts of other stuff.
As mentioned above, you don’t need higher energy to defeat body armor, just more concentrated force. Sad story from a friend of a friend, but some young soldiers once demonstrated this with an ill-fated bet. A Kevlar armor-wearer insisted that the flak vest he was wearing would stop a knife thrust to the center of his chest. He lost the bet in the most tragic possible way.
---
### Author:  [@Melbourne](https://boards.straightdope.com/u/Melbourne)
#### Post date: [September 18, 2025, 10:14pm UTC](https://boards.straightdope.com/t/is-depleted-uranium-at-all-useful-for-defeating-body-armor/1023168/7 "2025-09-18T22:14:52Z")
> [@kenobi\_65](#):
>
> Well, the stuff is apparently pretty toxic:
It is less toxic than lead [Depleted uranium instead of lead in munitions: the lesser evil - PubMed](https://pubmed.ncbi.nlm.nih.gov/24594921/)
---
### Author:  [@yendis](https://boards.straightdope.com/u/yendis)
#### Post date: [September 19, 2025, 1:03pm UTC](https://boards.straightdope.com/t/is-depleted-uranium-at-all-useful-for-defeating-body-armor/1023168/8 "2025-09-19T13:03:10Z")
> [@HMS\_Irruncible](#):
>
> The main benefit of DU rounds is how much kinetic energy they can deliver. So it wouldn’t be enough just to make DU bullets, there would need to be more propellant, which would require a sturdier barrel, and all sorts of other stuff.
Not necessarily. Armor piercing rounds with tungsten or tungsten carbide cores exist, and tungsten has a similar density to depleted uranium. Those rounds can be put through standard weapons without modification.
---
### Author:  [@Jasmine](https://boards.straightdope.com/u/Jasmine)
#### Post date: [September 19, 2025, 1:43pm UTC](https://boards.straightdope.com/t/is-depleted-uranium-at-all-useful-for-defeating-body-armor/1023168/9 "2025-09-19T13:43:35Z")
I thought “armor piercing bullets” handled that. In any case, I really, REALLY don’t want to see thousands and thousands of expended radioactive rounds all over the place. 😳
---
### Author:  [@bump](https://boards.straightdope.com/u/bump)
#### Post date: [September 19, 2025, 1:44pm UTC](https://boards.straightdope.com/t/is-depleted-uranium-at-all-useful-for-defeating-body-armor/1023168/10 "2025-09-19T13:44:55Z")
> [@crowmanyclouds](#):
>
> To put it in other terms, a fist will not penetrate body armor but the same amount of force with an ice pick will.
Armor piercing sabot rounds need highly dense and very hard materials to be maximally effective. Tungsten is the third most dense element, and is also extremely hard, and relatively common. That’s why it’s often used in APFSDS rounds. But it’s not super-common and is extremely brittle and hard to machine.
However, depleted uranium is nearly as dense, much easier to machine, and has a couple of other properties that make it great for armor piercing projectiles. First, it’s self-sharpening. Some property of the material mean that it basically keeps itself sharp as it penetrates. Second, it’s got what are called pyrophoric properties, which means that once it has penetrated, the pieces tend to catch on fire spontaneously and set everything else on fire that they touch. And to top it all off, in the Cold War US, depleted uranium was essentially industrial waste that didn’t have much value beyond being used for relatively boring things like really dense weights for things like airliners.
The combination of all that means that while tungsten is extremely good, DU is better still.
But that’s in tank shells. Body armor operates in an entirely different and much lower regime of energy, and penetration doesn’t really have much to do with the density, as much as just shape and force.
---
### Author:  [@HMS\_Irruncible](https://boards.straightdope.com/u/HMS_Irruncible)
#### Post date: [September 19, 2025, 2:37pm UTC](https://boards.straightdope.com/t/is-depleted-uranium-at-all-useful-for-defeating-body-armor/1023168/11 "2025-09-19T14:37:34Z")
> [@yendis](#):
>
> Not necessarily. Armor piercing rounds with tungsten or tungsten carbide cores exist, and tungsten has a similar density to depleted uranium. Those rounds can be put through standard weapons without modification.
Right but they weigh about the same as regular ammunition because it’s just a tungsten core with a thicker jacket, because tungsten causes more barrel wear, and the benefit is more about the hardness than the weight. Tungsten is actually denser than DU, so DU wouldn’t offer any advantages there. It’s also more expensive than DU.
DU is advantageous when you buy it by the ton, for applications that need to put hundreds of pounds per minute downrange, and the kinetic energy is more important than the hardness. Body armor penetration is just a different application.
---
### Author:  [@xtenkfarpl](https://boards.straightdope.com/u/xtenkfarpl)
#### Post date: [September 19, 2025, 6:14pm UTC](https://boards.straightdope.com/t/is-depleted-uranium-at-all-useful-for-defeating-body-armor/1023168/12 "2025-09-19T18:14:10Z")
> [@Lumpy](#):
>
> Given the glowing reports of the near-magical effectiveness of depleted uranium projectiles, is this being at all considered for rifle rounds intended to defeat body armor?
I can’t see why depleted uranium would be any better than several other elements of similar density and hardness. Tungsten or rhenium, for example.
U238 isn’t particularly radioactive, and that doesn’t matter at all in this application. I suspect there is a certain amount of ‘magical thinking’ going on in those reports?
---
### Author:  [@smithsb](https://boards.straightdope.com/u/smithsb)
#### Post date: [September 19, 2025, 6:55pm UTC](https://boards.straightdope.com/t/is-depleted-uranium-at-all-useful-for-defeating-body-armor/1023168/13 "2025-09-19T18:55:05Z")
> [@bump](#):
>
> That’s why it’s often used in APFSDS rounds. But it’s not super-common and is extremely brittle and hard to machine.
>
> However, depleted uranium is nearly as dense, much easier to machine, and has a couple of other properties that make it great for armor piercing projectiles. First, it’s self-sharpening. Some property of the material mean that it basically keeps itself sharp as it penetrates. Second, it’s got what are called pyrophoric properties, which means that once it has penetrated, the pieces tend to catch on fire spontaneously and set everything else on fire that they touch.
DU is also difficult to machine because of its pyrophoric properties and hardness. Requires separate facilities and equipment (machined under an oil bath for starters). For the quantities (millions of rounds); just not practical for small arms. The US liked it for large caliber tank rounds (105mm and 120mm), 30mm rounds for the A-10, and some specific niche rounds for the penetration and incendiary properties.
The US (I helped for a couple of days) expended some energy to recover penetrators and any large fragments of same after Desert Storm. Tyvek suits and masks/gloves required. The Iraqi T-72s and other armored vehicles were easily penetrated and in most cases, through and through. The projectile/penetrator shape was highly classified at the time (drawing showing dimensions and characteristics was SECRET). I don’t remember health benefits to the local inhabitants as a major concern at that time.
The US DU was very inert with health concerns related to spalled or shaved off particles being ingested (don’t lick the penetrator) or inhaled. Soviet use was a bit more dangerous. One of their small air-to-air missiles had a DU encased warhead. My friend discovered a cache left behind by the Soviets at Kandahar, Afghanistan. Conveniently had the RadHaz sticker on them. I’ve got pictures! Notified higher HQ; a plane was dispatched with a team of guys (no uniform/visible ID) who disassembled the missiles and took the warheads back for analysis. He, later, I had the disposal task for the remainder. Much later in Desert Storm II (a poorly rated sequel), we came across a much larger batch at Objective Arlington and surrounding airbases. I reported but not as much excitement about retrieval (they’d get around to it). I was cautioned to segregate the quantities in separately spaced stacks, no more than a dozen in each, to reduce any radiation hazard. Good times.
---
### Author:  [@bump](https://boards.straightdope.com/u/bump)
#### Post date: [September 19, 2025, 7:07pm UTC](https://boards.straightdope.com/t/is-depleted-uranium-at-all-useful-for-defeating-body-armor/1023168/14 "2025-09-19T19:07:59Z")
> [@smithsb](#):
>
> DU is also difficult to machine because of its pyrophoric properties and hardness. Requires separate facilities and equipment (machined under an oil bath for starters).
Oh, it’s not _easy_, but it’s easier than tungsten.
From what I understand, most of the issues with DU aren’t with radioactivity, since it’s mostly U238, and is less radioactive than naturally occurring Uranium. On top of that it’s an alpha emitter, which is relatively easy to mitigate.
But it’s a heavy metal, and like some of them, it’s very toxic. Think about the uproar if someone fired lead, mercury, or cadmium rounds? It’s basically the same thing with DU.
---
### Author:  [@Lumpy](https://boards.straightdope.com/u/Lumpy)
#### Post date: [September 19, 2025, 7:33pm UTC](https://boards.straightdope.com/t/is-depleted-uranium-at-all-useful-for-defeating-body-armor/1023168/15 "2025-09-19T19:33:39Z")
Presumably a radon hazard if stored in an enclosed space? Or is the half-life so low you’d wait decades before much daughter products built up? **ETA:** for that matter, when refining uranium for nuclear purposes you’d want to remove all the radium, polonium, etc. so what do they do with it?
---
### Author:  [@Dissonance](https://boards.straightdope.com/u/Dissonance)
#### Post date: [September 19, 2025, 7:39pm UTC](https://boards.straightdope.com/t/is-depleted-uranium-at-all-useful-for-defeating-body-armor/1023168/16 "2025-09-19T19:39:34Z")
> [@Lumpy](#):
>
> Submachine guns firing pistol rounds have been displaced by Personal Defense Weapon calibers
The standard SS190 round for the P90 with a steel penetrator and an aluminum core will go through a Level IIIA Kevlar vest at 200m. [FN 5.7×28mm - Cartridge types](https://en.wikipedia.org/wiki/FN_5.7%C3%9728mm#Cartridge_types).
> [@HMS\_Irruncible](#):
>
> The main benefit of DU rounds is how much kinetic energy they can deliver. So it wouldn’t be enough just to make DU bullets, there would need to be more propellant, which would require a sturdier barrel, and all sorts of other stuff.
This. The OP is essentially looking to use a sledgehammer to kill ants.
---
### Author:  [@bump](https://boards.straightdope.com/u/bump)
#### Post date: [September 19, 2025, 8:06pm UTC](https://boards.straightdope.com/t/is-depleted-uranium-at-all-useful-for-defeating-body-armor/1023168/17 "2025-09-19T20:06:16Z")
U-238 is radioactive, but only in the most strict sense. It’s half-life is 4.5 _billion_ years, which means that it’s not very radioactive at all, as such things are reckoned.
---
### Author:  [@smithsb](https://boards.straightdope.com/u/smithsb)
#### Post date: [September 19, 2025, 8:30pm UTC](https://boards.straightdope.com/t/is-depleted-uranium-at-all-useful-for-defeating-body-armor/1023168/18 "2025-09-19T20:30:39Z")
> [@Lumpy](#):
>
> Presumably a radon hazard if stored in an enclosed space? Or is the half-life so low you’d wait decades before much daughter products built up?
Another anecdote from my mind’s wayback machine. I’m at Seneca Army Depot, early 80s. First shipments of 30mm DU rounds coming in. 588 rds. in a CNU-309\* container, two containers unitized together (big metal boxes). The initial guidance is to park the incoming trailers, doors opened, in the suspect trailer area (with guard). After one hour, we were to inspect the interior for radiation leakage (existence?) with our AN-PDR something (it WAS a long time ago). With radiation meters, you have to get a background reading (zero the scale sort of) because _RADIATION IS EVERYWHERE PEOPLE!!._ Turns out that the SUN is a big source of radiation; who’d a thunk it! So, saving you the suspense, zero in the trailer. Next, take to the inspection bay, remove container top, leave opened for 24 hours. Next day monitor for radiation in the container. You would be surprised how much _RADIATION_ is put out by fluorescent lights! The ammo in the container - zilch. Those requirements lasted about 3 months until cooler (saner?) folks prevailed and stopped the nonsense. Again, please don’t lick the projectiles especially if the paint is scraped off!
\*yes, I had to look up the container number. It WAS 45 years ago.
---
### Author:  [@Airman\_Doors\_USAF](https://boards.straightdope.com/u/Airman_Doors_USAF)
#### Post date: [September 20, 2025, 10:47pm UTC](https://boards.straightdope.com/t/is-depleted-uranium-at-all-useful-for-defeating-body-armor/1023168/19 "2025-09-20T22:47:00Z")
The density and the shape of a round would certainly help in penetration, but the weight of the rifle required to fire it (remember, greater mass by definition equals greater recoil), the weight of the ammunition itself, the amount of powder and the required chamber pressure to send it with enough velocity… you’d need a tank. Which is why tanks and aircraft are the ones that use DU rounds to begin with. They certainly wouldn’t be wasting rounds on a single person, and if a person catches a round no body armor is stopping it.