Garrett's own account also mentions the five live rounds. This is a quote from his book about the kid ( The authentic life of Billy the kid) it was published in 1882. "We examined his pistol-a self cocker( double action, colt thunderer), calibre .41. It had five cartridges and one shell in the chambers, the hammer resting on the shell, but this proves nothing, as many carry their revolvers in this way for safety; besides this shell looked as though it had been shot some time before" As far as the explaination, this book was marketed towards easterners that would not know about these things. Think about it, how many "gunfighters" or cowboys would read a book about Billy's death? Turns out not many as Garrett's book was a failure.