composite armor

I've been readin a few articles on wikipedia about how great the challenger II and Abram tanks are. Does anyone know any disadvantage that the composite armor may have?

yes of couse they're vulneranble to DU rounds( in the right spots) the abrams latest Du penetrator can penetrate 960 mm of cadavnced armor at 2000 meters fprado.com... cseserv.engr.scu.edu...

sldo no matter what tanks are vulnerable from top attack munitions
en.wikipedia.org... read this dont forget a simple 10 punds of explosives detonated inder a tank can disable it. not to mention on tanks suchas the chally or abrams from the top the engine is abrely protected just shoot it there. tanks are deadly vs other tanks but they are not invincible ( as a lot of people on this forum think)