A third sniper (Sniper 3), who is probably on the roof of the Dallas County Records Building (where a shell casing was found in 1976), fires his first round at almost the same instant. However, the Presidential limousine slows down unexpectedly, and the bullet hits Governor Connally instead of JFK. Sniper 3 is probably not using explosive/frangible bullets. He may however be using sabot rounds: a 6.5 mm bullet in a 7.62mm (.30 caliber) plastic jacket, which it loses as the bullet leaves the barrel. This permits you to take a bullet that has already been fired say from Oswald's rifle), and use it again without adding any striations. The sabots are used to ensure Oswald's patsydom. I believe that Sniper 3's rifle also had a sound suppressor.
The Kill Shot. I think that all of the snipers had an order to aim for the head, and make sure JFK is dead at the spot which would become frame 313 of the Zapruder film. I think Sniper 1, with the Mannlicher-Carcano, may have had another misfire. This time the round's primer failed to ignite, which is the reason there are two shell casings and one live round in a photo of the TSBD's sniper's nest. Snipers 2 and 3's bullets hit the President almost simultaneously, killing him, and placing this nation on its current course of a somewhat benevolent dictatorship.
Why do I think that Snipers 2 and 3 were using sound suppressors? Because of the varying number of shots heard by the witnesses in Dealey Plaza that November afternoon.
Misnamed "silencers" in popular fiction, sound suppressors work by slowing the release of the expanding gases created when the primer ignites the powder inside the shell casing to drive the bullet out of the barrel.
Since at least the Second World War, suppressor technology has existed that permitted a semi-automatic pistol to be fired at 98%+ of its normal muzzle velocity, while minimizing the sound output to the gun's mechanical action, plus the sound of the round breaking the sound barrier as it left the barrel. It is for this reason that subsonic weapons and ammunition--such as the .45 ACP--are preferred as candidates for suppressed weapons: no tell tale "crack" as the bullet breaks the sound barrier.
I know that by 1968, the suppressor technology for rifles had improved enough so that a suppressor was optional equipment on the Army's M-21 sniper rifle, a heavily modified variant of the standard M-14. It was reportedly so quiet that--with the suppressor in place--you could not hear its mechanical workings, or the crack of the bullet going supersonic, outside 100 yards. The 7.62 NATO/.308 Winchester round that the M-21 used, reportedly lost less than 1% of its performance with the suppressor in place. (All of this is from some long lost issue of Soldier of Fortune magazine from the late 1980's. I am sorry that I do not have an exact issue to refer to.)
I do not think that I am going out on a limb to assume that the National Security State had equivalent, or near equivalent, suppressors available to them in November, 1963.
The reason that my hypothesis is important is this: if you can only hear the sound of the M-21 with suppressor in place at distances of less than 100 yards; you would logically have to be in just the right place in Dealey Plaza to hear either one or both of the two suppressed rifles that I am hypothesizing here. If you are in one place you hear only three shots; fifty feet to your right, someone else hears five.
The inability of the witnesses in Dealey Plaza to agree on the number of shots fired that grim afternoon is emblematic of this nation, and its struggles, for the last forty-six plus years.
We have become a nation that is so hung up on the minutiae, that we have forgotten the most important facts in our lives.
We worry more about political correctness and the right to bear arms, than we do about freedom of speech and of the press, as our right to know is buried in media mergers, news driven by profit, and mindless gossip.
We worry more about a woman's right to choose and a fetuses' right to live, than we do in caring for that woman before the child is conceived, let alone born, or caring for the child after he or she is born.
We worry about the United States remaining the dominant military power in the world; while as an economic power, which controls its own destiny, we have already fallen into the second tier of nations.
We must never forget the words from President Kennedy's inaugural address, "Ask not, what your country can do for you, ask what you can do for your country."
I think its time to go do something.