this is from the official report on the tank sent back for repair after the incident,
http://www.strategypage.com/gallery/images/solved1.jpg
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MEMORANDUM FOR RECORD
The following information is provided concerning a Malfunction/Accident/Incident involving TACOM equipment:
a. Location of MAIR: Baghdad, Iraq
b. Date and Time of MAIR: 5:20 AM (before dawn), 28 August 2003.
c. Identification of Unit involved: 2/70 Armor Battalion, 1 AD
d. Injuries/Fatalities: The Tank Commander received minor shrapnel wounds to the legs and arms and the Gunner got some in his arm.
e. Identification of Weapon/Ammunition/Equipment/Vehicle (SN, bumper #, ammo lot #) Involved: M1A1 Tank, serial number L13170, bumper number B 24.
f. Property Damage: The #4 right-hand skirt (TM 9-2350-264- 24P-1 dated March 2003, Figure 274, Item 17, NSN 2510-01-166- 2049, p/n 12323656), the Hull, the NBC hose behind the Gunner’s Seat (TM 9-2350-264-23P-2, dated April 2003, Figure 225, Item 13, NSN 4720-01-320-5774, p/n 12324460-9), the back of the Gunner’s seat (Figure 137, Items 1 & 30, Frame NSN 2540-01-362-5768, p/n 12931155, Cushion NSN 2540-01-144-1458, p/n 12312153), the safety guard that stands upright on the loaders side of the slip ring cover (Figure 132, Item 28, NSN 1015-01-250-5976, p/n 9377649), and the TNB (Figure 139, Item 22, NSN 5975-01-316-9270, p/n 12549752) were all damaged. The skirt and hull can be repaired by the unit, the safety guard is still serviceable, and they can replace the others. The TNB is beyond repair because the housing is damaged.
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the material penetrating the armour left a pencil sized hole on the tank, i don't know what is your medium size of course, so perhaps that qualify. despite the size of the dmg to the tank though, the material produced enough heat to trigger the internal halon fire extinguisher. And from the photo of the impact location i cannot see how the penetrator can hit fuel tank or engine.
And comparing the record with challenger 2 is quite impossible, granted that the millitary released very limited report on attacks against their forces in occupational duty. The reports that are available obviously shows more hummer, abrams, and bradley damaged or destroyed (no abrams have been destroyed by enemy warhead ever yet) than any other modern vehicles used by the other western force, but at the same time they are also the one getting shot at most often. Sure, there haven't been as many record of other MBTs damaged beyond field repair, but how many modern MBTs are actually getting shot at? The abrams by the simple fact of being in a hostile condition would receive a heck a lot more heat directed at them than most other MBT, so it's natural to see some of them taking damage.