So I tried it...
S&W 432, .32H&R Mag 100gr "Cowboy Load" Georgia Arms, 7 yards
Not bad at all. Really, really fouled the gun though, I need to find out if it's moly lube or graphite filler or if I've coated the front of my cylinder with metallic lead, but it's shiny now, and that's bad on a black gun.
I need to get my SP101 to the range and see if I do better, and if it fouls as badly.
I should have snagged a scoopful of the 9mm and run it through the Tanfoglio, but I forgot.