I'm assuming you are a machinist of some ability, so good luck in your efforts to resurrect this Smith frame from the dead; but in all honesty, if you've not attempted something like this before, you don't have a clue as to what it is you are undertaking. I again encourage you to take my advice and spend a few extra bucks on a more worthy project. As to the roll check and ejectors, I've examined a very early roll check gun Hunter Arms converted to auto-ejectors. They removed the roll and plugged the hole in the lug; they then modified/re-drilled the hole in the barrels for the shell extractors to accommodate ejector stems (and they also made an entirely new ejector forend iron and wood). This was all custom work done in the Hunter Arms repair shop.