Manny after what I saw the Sumatra 22 caliber do, to the steel on my very heavy gauge steel pellet trap I am not surprised that it penetrated both sides of the skull. I also shot it at about 65 yards at a spinner made for PB's and the pellet removed a 3/4 inch circle in the finish where the pellet flattened out, on the lower setting it made a very neat small circle but full power the difference in size was amazing. So far I have been totally amazed at the sheer power and accuracy of the 22 caliber Sumatra, I just did not expect such accuracy from a gun designed more for hunting than target shooting, really impressive, Neil.