The problem with putting a 5 shot cylinder in an Old Model Ruger is that conventional wisdom will make it a 4-shooter. Either carry it with an empty chamber under the hammer or depend on the quarter cock.
A friend has a 5x.38 OM Single Six and it is a real cutie, but of limited utility.
I'd rather round up a .32 H&R Ruger. If I wanted more zip, I'd have it converted to .327.
John Gallagher said he was leery of a .38 NM SS because of the risk of cutting into the hammer block channel. But would not mind making a 9mm. Hmm.