Been trying to break the habit of checking my computer each day. This site seems to be intoxicating went we're actual talking Civil War.

Anyway, you express some interesting, not usually thought of, points. The military usually does things because they follow a military logic. These points would seem to follow that military logical reasoning. Althought I don't think that they would be thinking that a canteen and havesack might stop a bullet, I can see the logic in turning the Cartridge Box away from being exposed. That is the reason why the infantry Cartridge boxes have tins in them that are divided into three compartments each, to maybe keep all of the cartridges from going off together should one of the cartridges ignite.

That may well be the case here that the benifits of exposing the left side to the enemy is an unintended byproduct of the practise of loading and firing the musket in a tight battleline formation. It may be that the writter here a just a keen observer of unintended consequences.