Info: Blackhawk 38-.40/10mm convertible was made years ago. If I remember correctly, the 10mm was the more accurate round in this gun.

My first hand gun was a Ruger .45ACP/LC Blackhawk 7.5". Still have it 30 some years later. I remember when the 38-40/10mm came out. I had just gotten turned onto 10mm DE's by a friend in the Navy and bought one at home when on leave. Have never seen one in person, though. I got my Dads' Single Six convertible when he passed (I think it is near 50 years old). My BIL had a .357/9mm I wanted. I would like to have a .45 with the shorter barrel along with a Super Blackhawk;)

UPDATE
Just ordered some from Topbrass-inc.com. Also ordered some last year directly from Starline.