I've several times run across reports of ammunition including a 'Butlers Bolt' and reference to a patent. Bolts as I understand them were armor piercing or shattering rounds. There have been discussions from time to time about a small rifled Butler gun captured aboard the Union blockader morning light. If there was a patented type of ammunition named Butler, I wonder if they built any cannon to go with the ammo, or just supplied for other manufacturers?