With all the current interest in "supply" (read "ammo wagons"), I thought one or two may be interested in some data to help understand the "historical" situation.
"During the war, a six mule hitched wagon could carry a maximum of 2000 pounds, less if the teams are new and pulling over rough and hilly terrain. Counting ammunition, food and medical supplies each man required four pounds of transport capacity per day translating into one wagon per 500 men if the wagon can make one round-trip per day from base of supply to point of distribution. Increase the distance to one day each way and the number of men supplied by each wagon drops to 250 and two days equates to 125 per wagon, on the face of it a simple mathematical equation. It is easy to see, however, that the increased distance coupled with a large army could easily out strip the capacity of a combatant to supply teams and equipment. Under this formula, an army of 100,000 men, ten days by wagon road from its base of supply, would require 4000 wagons, a large number yet it falls in the upper range of the number utilized by the Army of the Potomac."
"This simple equation, however, fails to make provision for fodder (feed) either for the animals attached to the army or for the supply teams. Each animal needed approximately 40 pounds of fodder per day. Since, in most cases, the supply teams had to carry their own, either individually or in specific trains, each day a team was away from the base it had to carry 240 pounds of its own food, reducing its capacity by 60 men. Diminishing returns legislates that eventually the teams will only be able to pull their own fodder."
"Supply is, in essence, based on mathematical formulas of which many were developed during the Civil War. In the above example, the actual numbers required to supply the average Civil War army of 100,000 with its attached cavalry and artillery ten days distant from supply base would be computed at 10,975 wagons utilizing 68,850 draft animals. This does not take into account wagons required to distribute supplies to the brigade level."
Whew! One heckuva of a lot more than you wanted to know, correct?
Incidentally, the supplying of artillery ammunition was via caisson/limber chests. Supply were seldom brought into the front line; rather, the caisson was sent to the rear to have the chests replenished.
J