Perhaps they are referring to this January 1861 cannon shot at Vicksburg: Link
The Governor of Mississippi was warned that Federal troops were coming down the river for action against Mississippi a la the Star of the West. So he stopped ships on the river to inspect their content. After inspection he let them proceed. A cannon shot was fired across the bow of one ship (or perhaps several) that did not heed the request to stop for inspection. Nothing was found in the inspections, so the effort to inspect ships was stopped after a few days.
Well, I am sure that some of our posters will give us a clarification.
So, what we have is the Vicksburg militia firing on Union shipping on January 13.
Now, one person here claims that the Charleston cannon that fired on the Star of the West was the first shot of the war.
But the Star of the West was a commercial vessel that had been engaged in coastal trade. Although hired by the Buchanan administration to deliver supplies to Ft. Sumter, the question of firing on a non-military ship as an act of war is up for grabs.
So, I might vote for the Vicksburg shot because it was between government shipping and militia.
But it has not been settled whether the first shot of the war had to be cannon, or could it be rifle fire?
That puts the federal troops at Ft. Barrancas into the running as firing the first shot.
So, the question of what constitutes a “first shot” is now on the table.
I wonder if anyone will pose the question of whether or not a shot fired is the first act of war, or maybe something else like calling up hostile troops or establishing a blockade of an opposing harbor would qualify as the first act of war.
You know, there is certainly enough information here to run this idea of "first to fire is guilty as sin" concept into the ground. But since it is important to our Union sympathizers here to affix the blame on the South, then let's see what they have to say.