U.S. M9 AT Rifle Grenade - 1.5 inches, M9A1 - 2 inches armor effective range both 75 yards.
U.S. 2.36 inch rocket - 3 inches armor effective range 400 yards.
Comment: In the film "To Hell and Back" Audie Murphy used a rifle grenade to succesfully damage the track of a Germantank that was being repaired. This incident was not mentioned in his book of the same title but presumeably recreated an actual incident.