Any Single-Six, Blackhawk, Super Blackhawk, Bisley, Bisley Vaquero, Vaquero or Old Army spring will work and all, but the O.A., are spec'd at 23# whereas the O.A. spring is 25#.
I wouldn't bother putting the O.A. spring in a rimfire. I'd save it for a fire breathing big bore!!!!
JMHO,
flatgate
PS While changing springs take the time to "detail" the mainspring strut and seat. Polish any/all friction producing surfaces. In addition, reduce the friction present in the hammer's fall into the hammer well. Often times the hammer well will exhibit roughness.....