Maybe a year or so ago, my gunsmith, Keith Warner of Memphis, told me he had acquired a Ruger .41 Magnum, a Three Screw Blackhawk. It was his intention to rechamber it for .45 Colt, case harden the frame and add a steel grip frame. He called me one day looking for a grip frame for a Ruger Blackhawk to replace an aluminum one his customer had broken.
I told him I had two, one steel and one aluminum. He bought both from me, saying he thought he could adapt the steel one to his Three Screw.
I found a trigger available from Dave Clements to adopt a New Model grip frame to fit a Three Screw. I was in his shop recently and told him abut the trigger and asked about his .45 Colt conversion.
He told me he had been shooting the .41 and decided he liked it too much to change it. Appears he's going to customize a .41 Magnum.