Correction on "no heat treatment" on Ruger frames. Ruger cylinder frames are heat treated before machining. This includes Single-Six models. Once upon a time Ruger heat treated after machining. At some point a change was made to avoid warpage, and treatment preceded milling. Heat treatment differs between chrome-moly and stainless, and is specific to alloy.
David Bradshaw
Rubbish. Alan Harton and many others I am sure can weld stainless with relative ease and all is perfectly safe too. Though not stainless Alan filled in the topstrap, where the original rear sight sat, on the 44 Special of mine and I still have all ten fingers.
Nice, but the question was about stainless, which offers distinctly different challenges from carbon steel.
For the most part, the answer remains that stainless CAN be welded, but it's risky if you don't know what you're doing, few gunsmiths are willing to do it, few CAN do it right.
Your average corner gun mechanic won't even try.
Denis