You said, "... smelled gunpowder as they were GOING PASSED the GK". The wind would Not permit a "drifting" gunpowder odor from the TSBD to the GK.
Correct. There is no way that the gunpowder drifted/traveled from the alleged sniper's nest to the grassy knoll area. Plus, several witnesses saw gun smoke above the fence on the grassy knoll, and a puff of this smoke is seen on the Wiegman film.
The two explanations offered to explain the apparent gun smoke in the Wiegman film are (1) motorcycle exhaust fumes and (2) smoke from the steam pipe in the railyard behind the knoll. Neither arguments works. No motorcycle exhaust fumes are seen on any film of the assassination, and the steam pipe was a good 100 feet away from the area seen on the Wiegman film.
Let us consider the witnesses who smelled gunpowder on or near the knoll:
Senator Ralph Yarborough rode in the second car behind the presidential limousine. He smelled gunpowder while on the street and said it clung to the car throughout the frantic drive to Parkland Hospital.
Elizabeth Cabell, the wife of Dallas mayor Earle Cabell, was in the fourth car behind JFK’s limousine. She said she “was acutely aware of the odor of gunpowder.” She added that Congressman Ray Roberts, seated next to her, mentioned that he smelled gunpowder.
Press photographer Tom C. Dillard, six cars behind JFK’s limo, said he “very definitely smelled gunpowder when the cars moved up to the corner” of Elm and Houston Streets.
Patrolman Billy Martin, riding just behind JFK’s limousine, said, “You could smell the gunpowder,” and that because of this he knew the gunman “wasn’t far away,” adding, “when you’re that close, you can smell the powder burning.”
DPD officer Joe Smith smelled gunpowder on/near the grassy knoll.
Journalist David Grant said that seconds after the motorcade sped from the plaza, “the area still reeked with the smell of gunpowder.”
Smith and Yarborough were war veterans, so they knew what gunpowder smelled like. Gunpowder has a very pungent, distinct odor.
The HSCA's acoustical scientists determined that the grassy knoll shot was fired from a location behind the knoll's picket fence that was near the area where several witnesses saw puffs of gun smoke on the knoll. Now that is one whopping, staggering coincidence, unless one is willing to believe that the HSCA acoustical experts rigged their analysis in order to place the grassy knoll shot in that location.
I discuss the gunpowder and gun smoke evidence at length in
A Comforting Lie: The Myth That a Lone Gunman Killed President Kennedy (pp. 157-159).