Another problem with using the "Topographical crest" of Missionary Ridge rather than the "Military Crest" was that when the Confederate would raise up out of their entrenchments to fire at the advancing federals they would be backlighted by the sky behind them making them excellant targets for the federal marksman. Also the Confederates from the Topographical Crest couldn't support their advance Rifle pits at the base of Missionary ridge once the federals got close to them.

Had the trenchs been laid out just 15 to 20 feet forward of the "Topographical Crest" along the "Military Crest". These problem wouldn't have occurred.

As for retiring by recoil that would only work when the ground was sloping away behind the guns or extremely flat and without obstruction. If you examine the ground behind the gun in Don T's Painting, I doubt that the gun would have "retired" very far.

In most cases, it is my understanding that the "retire by recoil" command was used when the gun was firing over the crest of a low ridge. The recoil would roll the gun back behind the ridge where the gun could be limbered using the ridge and the smoke created by the shot as protection and hide this activity from the enemy.

Unlike "retire by prolonge" command, "retire by recoil" wasn't intended to be used as a fighting retreat manuver.