"Sighting in" a rifle is an adjustment of the telescopic sight. When a
rifle has been disassembled, treated roughly, or gone unused for an
extended period of time, its scope must be readjusted or else it cannot
be aimed properly. The process simply involves aiming at a target, and
repeatedly firing while adjusting the scope until the target can be hit
accurately and consistently; the process may be expected to consume about
a dozen rounds of ammunition. Critics of the lone assassin theory point
out that had Oswald carried the disassembled Mannlicher-Carcano into the
Texas School Book Depository, its telescopic sight would be useless; the
gunman would have to remove the sight and aim with the rifle's iron
sights. The telescopic sight was, of course, mounted permanently on the
alleged murder weapon. The sight was also defective -- impossible to aim
during the FBI's subsequent test-firings until it had been reinforced
with metal shims -- and mounted to favor a left-handed shooter. It is
believed that Oswald was right-handed, though the Warren Commission was
unable to prove it. For the record, the rifle was also a poor quality war
surplus model: the Mannlicher-Carcano had been known during World War II
as the "humanitarian rifle," as it was said not to be able to hurt anyone
ON PURPOSE -- which also featured a defective ammunition clip and a worn
firing pin which worried its FBI test-firers that it might indeed explode
at any pull of the trigger.