A round fired from a rifle and a pistol are so different in power it is not even a fair comparison.
Discounting the fact that the round which hit the toughbook is probably fired from an higher calibre AK, even a 5.56mm round from a M16 can *easily* slice through the entire Macbook Pro like it is not even there.
Aluminum is a really soft metal you know.
According to The Inquirer, bullet experts had responded saying that the toughbook was hit from a low calibre bullet at a distance. I agree. Just by looking at the toughbook's entrance wound...a 5.56 AK round would have ripped that thing open (and produced a much larger point of entry). No doubt resulting in an exit hole on the backside.
I am assuming a mugging is much closer. Dont underestimate a pistol. a glock 9mm has enough stopping power. I highly doubt those muggers were using .22 pistols. At least 9mm.
http://www.digg.com/tech_news/The_Laptop_That_Saved_a_Soldier_s_Life
http://www.theinquirer.net/default.aspx?article=37615
at least the MBP works. The bullet in the toughbook got lodged in the keyboard probably crushing the motherboard.
Also, the angle of the bullet has the MBP at an advantage compared to the Toughbook. No doubt if it were hit at a perpendicular angle it would've went straight through, but instead it was hit at probably the strongest part of the MBP. Despite aluminum being soft, the malleable characteristics undoubtedly absorbed much of the energy of the bullet. Think of it as the "crush" zone found on every car.