I would call Greenmountain and speak to someone about your needs. In this modern time it seems that there are problems understanding just what is available from an online description. If you can talk to an airbreathing, real person,you should get your answer quickly. I have a Hawken model with a 54 caliber roundball barrel,it shoots closer than I can hold it. I also have a 50 caliber,Longrange Hunter,both of these barrels are made by Greenmountain,and are prized possesions.
Don't worry about the mule going blind boy,just load the wagon.