Hello Glen;
Yes, Bain's Battery was definately not at the Battle of Shiloh. There is plenty of sources that verify this. This mistake stems from the Organization Report of the army compiled by Colonel Thomas Jordan on April 3rd. This is a statement of the army on April 3rd. It does not reflect changes with the army that marched out of Corinth on April 5th. The Vaiden Mississippi Artillery (Bain's Battery)is one of these changes. Another example is the 51st Tennessee infantry and eight companies of the 52nd Tennessee infantry were left in Corinth as part of the garrison.

You mention that one gun of Stanford's Battery was left behind as defective. This is the first I have heard of this. Can you provide source of your information? Can the source be the diary you mention and what is this diary?
Ron