[quote="mburduck"]So, would the 105 with AP round make a good anti-tank weapon?
According to a test conducted by the US First Army, yes the 105mm howitzer's HEAT shell (shaped charge warhead) would penetrate the frontal armor of a captured Panther tank at 500yds range (the only other US gun that could do that was a 90mm AAA gun). The bad news is that at 500 yds the Panther can kill you REAL dead! Another problem is getting a hit. A 105 howitzer is meant for indirect fire, so even at close range it has a curved trajectory. A good gunner can do it, but it isn't like putting the cross hairs with a high-velocity gun and pressing the trigger. Most of the M4/105H and M4A3/105H that saw service in the ETO didn't have power turret traverse which made it trickier to use as an AT weapon.
Fortunately the 105 was useful against the most common enemy - dug in AT guns and infantry with portable AT weapons. Despite the claims on History Channel shows, these were the big killers of US tanks.