I was interested in your statement that a .22 Magnum would not even fit in the frame window as I have one of the above mentioned "star" marked 4 5/8" stainless Single-Sixs that is a Long Rifle only gun....
Pulled the cylinder from a new Single-Six Hunter .22/.22 Magnum and the cylinder dropped right in the "star" marked gun...
You may want to ask over on the Ruger Forums...
Great buy on that gun...Bob