"Did they do it?"

I seriously doubt it. If I were a gun commander, in charge of a piece, I wouldn't have.

Very few field artillery pieces, such as a 12 pounder with a bore of 4.65 inches in diameter, would have the bore size to actually stuff a leg down the barrel. There were very few 24 pounders, which had a bore diameter of 6 inches, or larger guns were used by either side. They were just too heavy to manuver on the battlefield for the effect that you got from their shells.

Even if you did have such a gun, or the leg was skinny enough, you would probably not get a good enough fit pressure wise for it to fly very far. But most likely all you would get is a bunch of red goop and hamburger meat, and probably foul your gun barrel for the next round.

A leg would not be a very effective round. So why waste your time? I am sure that this statement was a last act of defiance, that the gun crew took as such, and continued their mission of providing legitimate fire suppose for whatever their fire mission was.