Ruger did not have a Practical holster for the SBH.. Because of the larger grip frame on the SBH I don't think the 7.5 " Blackhawk holster will fit well. The flap may not fasten. Maybe someone will do a test for us.
The 7-1/2" Cathey holsters also work with the OM Super Blackhawk. They look identical to the Bianchi holster except have a little different marking on the loop and aren't marked Bianchi.
There might have been fewer of those made though than the Old Army Bianchi holster.
Chad
Just FYI......I have a Ruger Practical Holster for a 7 1/2" OM SBH. I assume it was mfg'd by Cathey since it doesn't have the Bianchi name on it. The back of the belt loop is indeed marked "SUPER BLACKHAWK 7 1/2" BARREL". The leather is darker than my Bianchi 4 5/8" Practical holster; the big one is more of an oxblood and the small one is brownish. John N.