Jim; I have been "doing" horse drawn artillery for a number of years, and have never heard the term of "retreat by recoil" I am fairly familiar with a number of drill manuals, and have never seen it in print.

It doesn't make a great deal of sense. My six pounder has about six feet of recoil with solid shot, and three feet with cannister. At that rate, it would take ten shots to move the gun 60 feet, which isn't much of a retreat. If you were actually doing it, you would have to turn both the limber for the gun and its caison and limber facing and moving to the rear to stay ahead of the recoil, as if you did not, three shots would insert the end of the handspike in one of the lead horses noses. Without further evidence I would relegate "retire by recoil" to the same repository as "fire in the hole" As to the Troiani painting, Bigelow's battery initially attempted to retire by prolong, but had lost about 45 of their 88 horses by the time this movement was attempted. They did reach a stone wall by the Trostle house, when they were ordered to in effect sacrifice the battery by holding the position at all hazards. By the time the men were ordered to abandon the guns and run for the rear, the battery had lost 80 of its 88 horses. The Troiani painting depicts the battery in its final semicircular position with most of its horses down. The "retreat by recoil" title I think gives credit to the battery that the only retreat would be the recoil of the guns, and does not indicate a command.

One other comment. In someones reply, they stated that CS teams were unhitched and taken to the rear. This might have been so in situations where there was a fixed position, but I have never seen this in regards to artillery in the field. The ideal line of battle location for a battery was the "military crest" of a ridge, where the gun was behind the crest, with the muzzle level slightly above the actual crest, so the gun received some protection. With the teams behind the gun, they received even more protection.

The primary concern of any battery was preventing the loss of a gun. Horses were expendable - guns were not, and the teams were kept close so that the piece could be limbered and moved quickly. It takes 3-5 minutes in optimum conditions to hook up a six horse team. More if you have an unruly or frightened horse. That's a relatively long time if you are being charged by a line of infantry.
Conversely, we can have a gun rolling to the rear in about 30-45 seconds from the command "limber to the rear" if the cannoneers carry implements rather than secure them.

I have seen references to drivers dismounting and either standing by their teams or even lying on the ground and holding the lead straps. A mounted driver is pretty high up off the ground and a very convenient target.

Randy