You may want to try the 220gr. hardcast Keith bullets from Leadhead Bullets.
www.proshootpro.com. I have been using their Keith style bullets in .45 Colt and .44 Mag, and they have performed great. I have just gotten in my first order of the .41 hard casts and have not had a chance to try them out yet.
I wil probably start with enough H-110 to get them going about 1325fps. or so out of my 4 5/8" Blackhawk.
If you ever are interested in going to a heavier bullet, I can recommend the 265gr. Veral Smith designed WLNGC bullet from Cast Performance.
I put them over 19.8gr. of H-110, that load is from the Hodgdons manuel, and they come out at 1208fps. from the same gun. It is a very accurate bullet, out of my gun anyway. Great penetration, very accurate, and the recoil is more of a "shove" than the "snappy" recoil of the lighter bullets I have tried.
I have spoken to the nice folks at Leadhead, and they do not put GC's on these bullets, they say that the bullets I am talking about can be driven to 1500+ fps. without any leading. I think that they probably know what they are talking about, seeing as they make all of the cast bullets for CorBon!
JMHO, and as always,YMMV
Willy