Depleted Uranium Penetrators

Ok, these two items are not really consumer products, unless you are in the arms trade. They are examples of depleted uranium penetrators used by the U.S. military.

The taller penetrator, on the left side in the photo to the right, is a 25 mm round fired by the "Bushmaster" canon carried by the Army's Bradley Fighting Vehicle (see photo below).  


The 30 mm penetrator on the right (with the red cap) is employed by the U.S. Air Force's A-10, also known as the "Warthog." Fired by a canon at a rate of up to 4,800 rounds per minute, its primary function is to destroy enemy tanks.  When fired, the plastic sabot at the top falls away leaving the pencil sized rod of uranium as the only projectile. The threaded bottom portion of the DU rod can be seen in the photo below right.  It carries no explosives. 


A major reason that uranium metal is used is that it is hard and dense.  The high density provides substantial momentum and a straight trajectory. It is almost impossible to stop. Tungsten can be used instead of DU, but DU has greater penetrability even though the two materials have similar densities. As such, the ability of DU to penetrate a target it is not purely a matter of momentum. 

Unlike tungsten, uranium is pyrophoric. It also has a lower melting point than tungsten. When a DU penetrator strikes a target, its surface temperature increases dramatically. This causes localized softening in what are known as "adiabatic shear bands," and the sloughing off of portions of the projectile's surface.  This sloughing action keeps the tip sharp and prevents the mushrooming effect that occurs with tungsten.

When the DU penetrates the target vehicle, the larger fragments tend to chew up whatever is inside and the pyrophoricity of the uranium increases the likelihood that the vehicle's fuel and/or ammunition will explode. The technical term used to describe these events is "behind-the-target effectiveness."

Some versions of the Army's M1A1 tank fire extremely large 130 mm DU rounds and, until recently, the Navy Phalanx system employed 20 mm DU rounds to shoot down incoming missiles. The current version of the Phalanx system employs tungsten rounds rather than DU.

I am grateful to Dr. William Flis for his helpful comments concerning some of the technical aspects of this page.

Click to view full-size JPEG photo

The U.S. Air Force A-10, better known as the Warthog.


Nuclear Metals Inc., brochure. Depleted Uranium Ordnance.

U.S. Army training document. Depleted Uranium Training for Chemical Soldiers. TA-031-DUAT-003.

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Last updated: 01/20/09
Copyright 1999, Oak Ridge Associated Universities