I don't happen to think three shots were fired in 5.6 seconds but set forth below is the relevant portion of the transcript of the CBS broadcast. This "could have done it, couldn't have done it" debate is endless. We will never know exactly what occurred. CT hyperbole - "proves!" "impossible!" - is just silly. One point Cronkite makes is, IMO, critical. No one will ever duplicate the adrenaline that had to be pumping through Oswald. The assumption always seems to be that the stress of a situation such as the JFKA would impair performance; in fact, adrenaline can result in faster reaction times and heightened focus, sometimes to an astonishing degree. Lastly, any notion that every clod off the street is a sharpshooter is nonsense; specific statistics are difficult to find, but in one Marine annual rifle qualification I found only 21% qualified as sharpshooters and the percentage typically cited is around 30%. CTers do themselves a disfavor when they resort to the sort of hyperbole they seemingly can't resist.
RATHER: Results varied. A Maryland state trooper made two hits in the
silhouette, one near miss -- in slightly less than five seconds.
Another state trooper's best time was 5.4 seconds. One hit,
two near misses,
A weapons engineer had the best score. Three hits in 5.2
seconds. A technician at the H. P. White Ballistics Laboratory
managed three shots in the fastest time, 4.1 seconds, half a
second faster than the fastest time turned in for the Warren
Commission, but only one hit.
Altogether the eleven volunteer marksmen made 37 attempts to
fire three shots at the moving target. 17 of those attempts
had to be called no time, because of trouble with the rifle.
In the 20 attempts where time could be recorded, the average
was 5.6 seconds.
CRONKITE: From our own tests we were convinced that a rifle
like Oswald's could be fired in 5.6 seconds or less, and with
reasonable accuracy, at a target moving much the same as the
Presidential limousine was travelling away from the Book
Depository's sixth-floor window,
So, clearly, there is no pat answer to the question of how
fast Oswald's rifle could be fired. In the first place, we
did not test his own rifle. It seemed reasonable to say
that an expert could fire that rifle in five seconds. It
seems equally reasonable to say that Oswald, under normal
circumstances, would take longer. But the circumstances
were not normal. He was shooting at a President. So our
answer is: probably fast enough.