You should go read the whole bit, by clicking this link.The U.S. Army is carrying out an aggressive development program to produce a new, lightweight composite armor for its next generation tank. This vehicle, part of the FCS (Future Combat System) series of vehicles, will weigh under 30 tons. The current U.S. tank, the M-1, weighs 70 tons. Composite armor was invented in Britain during the 1980s. The British developers had found that layers of different metals and ceramics made the armor lighter, and more resistant to penetration by solid shot or HEAT shells. The U.S. added a layer of depleted uranium to its composite armor, and produced the most penetration resistant tank armor ever.
Now U.S. Army developers are betting that they can come up with breakthroughs in composite armor design that will produce protection equal to what the M-1 now has, but at less than half the weight. The army developers are doing it by trial and error, making some progress most months. It's still unknown if the new lightweight armor will be there in time for the new tank's debut date in 2015.
Here's another very-short-lived Chrysler product:

What d'you think we were trying to accomplish with this beastie?
Geez, I figured an Auld Soldier (and an Arty guy at that) would know that.
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1. "Auld Soldier" is a title around here. My Dad. Who *is* an auld artilleryman, though he seldom weighs in on whatziss'.
2. You assume I *don't* know what the design was intending.
3. You are closer than you realize.
Range target, or Decoy mockup are my bets.
"You are closer than you realize."
Now that's a scary thought....
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I was certainly wondering about how it elevates and traverses, too...the lack of sharpness and contrast obviously aren't making it very easy, but I think I can see what MIGHT be a part that allows the barrel to elevate. Look where the very sharp line forming the "crease" around the turret thing abruptly becomes soft, just to the left of where the barrel protrudes. It could be nothing, or it could be a sort of a hinge. As for the ability to traverse...I just can't see how that turret can move, I think the idea was that the whole vehicle should be rotated instead of just the turret...maybe, before the days of the M1's fancy fire control system, they decided that tankers shouldn't be shooting on the move?
Crew survivability in an NBC environment. The whole crew is in the turret.
Scrol down.
http://www.secretprojects.co.uk/forum/index.php/topic,673.0/highlight,nuclear+tank.html
Interesting thing about nuclear rounds is that you actually can't really make them small enough to fit in tank barrels (at least not of traditional bore sizes).
http://findarticles.com/p/articles/mi_m1316/is_v19/ai_4696991/print?tag=artBody;col1