Barrels of the 77/CF models have, to my knowledge, always been threaded into the receivers. Until recently, the RFs were slip-fit and clamped like 10/22 barrels, but are now also threaded.
Your idea is a good one, actually one I have mulled over at times along with turning a 77/44 into a 77/357 B&D.
The nice lady at Ruger parts sales told me that the plastic stocks for the 77/44 and the 77/357 are the same which leads me to think that a walnut 77/44 stock could be fitted to a stainless 77/357, which would be quite handsome, I think. The main obstacle would be finding a stock as Ruger doesn't have any extras lying around waiting for my good ideas.
