Search Jet Bullets. He sells cast bullets for many caliber, including the .44-40 that are made of a softer alloy which often works better in these older rounds. The.44-40 especially can have a variety of barrel / chamber diameters so softer and larger is often better. Starline brass should be available in lots of places such as Rusty Woods, Ellwood Epps, etc. Add a can of Unique powder and you are set.