It has been said that at Spotsylvania the Confederates used their artillery like giant shotguns. Short ranges and the need to add power to the infantries line necessitated just that. The guns by and large were in the trenches, firing against massed infantry at generally only a few hundred yards.
Perhaps the records can shed some light on this one way or another. Below is a table, taken from the Official Records, showing the amount of artillery ammunition remaining in the ANV ordnance trains on May 18, 1864.
What is interesting about this table is the distribution of rounds, by type, remaining in each Corps trains. Remember this is not the number at the actual batteries. We can assume that the ammo chests for those guns were kept as full as possible. We can also assume that each battalion had a supply of sorts on hand. What that supply consisted of,if it existed at all, we do not know. But once those rounds were fired, whats listed in this table is all that’s available until a new supply arrived from Richmond.
What we can surmise from looking at this table is not the number, but the type of ammunition that was being used. For the sake of argument we will assume that each corps started out with roughly the same number of say, Napoleon shot, when the campaign began. So what would cause a difference in the number remaining?
The Second Corps numbers could be skewed by the loss of so many guns and their ammunition on May 12, but that would mean less guns to consume ammo afterwards.
The thing that jumps off the page to us is the shortage of canister. 24 rounds of napoleon canister, all in 1st and 3rd Corps. 54 rounds of 3 inch rifle canister that was all in 3rd Corps.
And of course Alexander in the 1st Corps was a strong proponent of the howitzer, thus the numbers for howitzer ammunition.
I would think that one of the tasks Confederate Artillery commanders had to contend with at this point of the campaign was fire control. Making sure that the batteries weren’t wasteful of ammunition. How much if at all it effected the battle we will probably never know.