Never heard of them before until last week. Ruger made the new model blackhawks for a Ohio company, Buckeye sports or something. The revolvers were 38-40 with a conversion cylinder for 10mm. Never heard of the 38-40 either. But the 10mm is nothin new to me! Never owned a single action gun before. I found one and many searches and can't wait to get it. It is new in the box and never fired, was even kept in a controlled temperatur safe. Looks pretty sweet in the pics. Cheaper option than doing the Ruger Gp100 conversion to 10mm. Not sure how many were made back in 1990, just a few hundred it seems like. I didn't buy a .41 mag because I didn't want one, I wanted a 10mm Ruger!!