The misconception in the strength of the shermans armor is related to the relative weakness of its gun and the impact on tactics. The low velocity gun tube forced the sherman crews to maneuver for close range kills. This not only exposed them to fire from enemy tanks and assault guns but played heavily into Rommel's preferred tactic of deploying anti tank guns forward of his armor. Normal successful engagement ranges for an M4 armed with the standard 75mm gun tube (M3L40) were 500M or less. Later versions equipped with the T23 turret (76mm gun tube) were able to engage not only PzIV's but also PZV/VI GV's on much more favorable (although not even) terms. The 46 degree slope on the shermans frontal armor was nearly identical to the T-34 and panther's. Significantly more shermans were lost to AT guns and infantry deployed AT weapons/mines then enemy tanks/TD's. If we view the german loss rates during the battle of the bulge we can see statistically very heavy losses completely absent US air power against units badly outnumbered and widely considered inferior and poorly equipped. US M10 equipped TD battalions (not to mention the M-36 equipped ones) repeatedly decimated German columns equipped with both Panther & Tiger tanks. While the M4 as originally configured is clearly inferior to all 1944 German AFV's the loss rate was as much a function of attack as anything else.
