QUOTE(Michael Crane @ May 10 2008, 02:59 AM)

Thanks again Jack.
Wouldn`t it be a coincidence if JFK was reacting to being shot just as he passed these zones in the Zapruder frames? Oh well, I found out what I was asking for by the helpful members on the forum.
Thanks again for the help.
All of this was long ago discussed on this forum.
The first shot occurred well prior to the Presidential Vehicle coming abreast of the first yellow mark.
The second shot/aka Z313 impact occurred just after the Presidential limo had passed the first of the various yellow curb marks.
Distance from the first shot to the second shot was some 100 feet, with a time delay in the vicinity of 5.8 to 5.9 seconds.
So! Exactly why did the shooter "wait"? One can only speculate, which would include:
1. Failure to fully eject first expended cartridge shell and "jam", requiring rework of bolt to chamber second round.
2. Target acquisition time through scope.
3. Waiting until target came abreast of known "distance/range" marker/aka yellow mark on curb.
4. ?????
Nevertheless, the third/last/final shot came just as the presidential vehicle came abreast of James Altgens, who also happened to be standing only a few feet from the second yellow curb mark.
Centerline to centerline distance from the first yellow mark (Z313 area) to the second yellow mark (Altgens area) was approximately 45 feet.
Vehicle speed estimated at 10mph = 14.66666 feet per second.
45 feet/14.66666 = 3.07 seconds of elapsed time between center of yellow marks at 10mph speed.
2.3 to 2.4 seconds of elapsed time required to get off a "good" shot with the Carcano, utilizing the scope.
Were the vehicle travelling at a rate of speed of approximately 12mph, then the elapsed time for the vehicle to have travelled from center of yellow stripe to center of yellow stripe would have been approximately 2.56 seconds.
All of which appears to be highly coincidential since the yellow curb marks also make good "range markers" as well as an aid in target acquisition when one has to utilize a scope.
With that stated, it remains as another of those "coincidences" which exceed the bounds of normal consideration.
Especially when one takes into consideration the addiltional yellow curb markings, only 4 bullets total in the Carcano, and the fact that after the third yellow mark, any subsequent shots would have been considerably difficult to achieve.
By the time that the Presidential Limo/aka/JFK/aka the target approached the third yellow mark and the fourth round was chambered, JFK was completely out of sight down in the vehicle and Clint Hill was obstructing any view from the sixth floor window.