I think you may have found a description of use of the Woodruff Gun. A somewhat controversial piece made for political reasons it was a lightweight cast iron or "steel" ( word oftentimes used to distinguish from the more oft used prewar brass)gun. It used a 2 pound projectile and was used to the best of my knowledge exclusively in the western theater, often bought by Infantry and Cavalry to augment their fire power by officers of the company or regiment. For more see
Battery B has a marvelous site and description online.
Another small bore light weight artillary piece was the Williams gun, a crank operated breechloader that fired a one pound projectile. Made at Richmond I belive it was an exclusive confederate piece.