Presidential Limos are armored, yes, but Gregg Merksamer reveals that George W. Bush’s limos sport five-inch thick glass, more than twice as thick as in Clinton’s limo. Merksamer should know, he wrote the book on so-called “professional cars”. He says half an inch is enough to stop a .44 magnum at point blank range, and BMW’s X5 “Security” model features only a little more than that. So what’s it mean when a person needs ten times that amount?