gp wrote: Wrong. HESH rounds don't enter anywhere. They are designed to create spalling without penetrating the armor. It is acknowledged that they are generally ineffective against spaced armor, laminated, composite armor and some types of ERA armor. Spalling is caused by a shockwave passing through the armor plate and breaking off pieces of the inside plate which can be propelled with considerable force. Other pieces inside the tank may be jarred loose but since the shockwave isn't propelling them directly it is doubtful that they would cause significant damage. Of course, considering the nature of the Abrams armor the HESH round wouldn't likely transfer enough force to the inside to cause either spalling or to jar loose equipment. Simple spaced armor will defeat the HESH round much less composite armor. Wrong. At the velocities and range we are dealing with the trajectory cannot possibly approach the parabolic curve you describe. The trajectory at 1400 meters is nearly flat, within a few degrees of horizontal. To calculate the trajectory you only need the ballistic coefficiency of the round and the velocity. Even though the HESH round trajectory isn't as flat as the extremely flat KE round round trajectory (>1600m/s) it is still relatively flat. I don't intend to tackle the math to settle this dispute because it is silly to even contemplate. With even the most basic knowledge of external ballistics the idea of striking near vertical from 1400 meters and at velocites greater than 1000 meters per second is ludicrous. One would need to aim nearly vertical such as with a mortar (with much lower velocites) and the main gun isn't even capable of elevating to near vertical positions. It doesn't use Chobham armor, strictly speaking. The armor is very similar in that it is a laminated,composite material , that uses ceramics imbedded in a matrix of other classified material. The Abrams also has steel encased DU. It's not too hard to understand. The Challanger and the Abrams' armor are quite similar in many respects yet different in some other ways. So do mine but the difference is that they aren't "war stories" or anecdotes of dubious veracity but are taken from published reports by the people who developed the weapons systems as well as those who use them. You made a similar claim about the erroneous statements you made regarding the altitude of A-10 attack profiles in the Gulf War until proven wrong.