 The United States developed its own kinetic energy penetrator ( KEP ) tank round in the form of an Armor @-@ Piercing Fin @-@ Stabilized Discarding @-@ Sabot ( APFSDS ) round , using a depleted uranium ( DU ) alloy long @-@ rod penetrator ( LRP ) , designated as the M829 , followed by improved versions . An immediate improvement , known as the M829A1 , was called the " Silver Bullet " after its good combat performance during the Gulf War against Iraqi T @-@ 55s , T @-@ 62s and T @-@ 72 tanks . The M829 series centers around the depleted uranium penetrator , designed to penetrate enemy armor through kinetic energy and to shatter inside the turret , doing much damage within the tank . In 1998 , the United States military introduced the M829A2 , which has an improved depleted uranium penetrator and composite sabot petals . In 2002 , production began of the ( $ 10 @,@ 000 per round ) M829A3 using a more efficient propellant ( RPD @-@ 380 stick ) , a lighter injection @-@ molded sabot , and a longer ( 800mm ) and heavier ( 10 kg / 22 lb ) DU penetrator , which is said to be able to defeat the latest versions of Russian Kontakt @-@ 5 explosive reactive armor ( ERA ) . This variant is unofficially referred to by Abrams tank crews as the " super sabot " . In response to the M829A3 , the Russian army designed Relikt , the most modern Russian ERA , which is claimed to be twice as effective as Kontakt @-@ 5 . A further improved M829E4 round with a segmented penetrator to defeat Relikt has been under development since 2011 and was to be fielded as the M829A4 in 2015 . 
