Three screw missing cylinder

On Wednesday, my coworker brought in a 1960 Old Model Three Screw magnum-only for me to look at/see about fixing up. He knows I love rimfire stuff, which is cool, but this thing is plenty rough. It is quite rusty, is missing its cylinder and all 3 parts of the firing pin assembly. The stocks are hand-made, whittled out of what looks like a 2x4. I hosed it down with Kroil and let it sit overnight. I got the cylinder pin out OK, scrubbed out the bore (also quite rusty) and got the ejector rod moving somewhat. The bore is now a bit shiny and the rifling appears crisp, but I can’t tell how much pitting is evident. I accidentally left the batteries in my mini Maglite that I use as a bore light with the out-of-production fiber optic attachment, so I can’t get the bore well-lit to see what’s what.

My questions: will a magnum cylinder from a later-production SS fit/function? I have a fluted magnum cylinder that I sourced for MY beat up rusty SS that I got for free a few years ago.

So my research shows that most Single Sixes have the firing pin bushing pinned with a 1/16” pin at an angle through the frame. The ‘60 has no such provision. I believe I have found a correct firing pin setup, but am curious if the bushing is just a press-fit. If so, does anyone have experience installing one without damaging (further) the revolver?

The grip frame is pretty beat up too. Someone used it as a hammer sometime in the past. My understanding is that the XR3 casting is correct and one must source stocks specific to that casting.

Luckily the trigger/action seems to function really nicely. I love the trigger pull on this thing compared to my New Model. I am worried that if I DO send it back to Ruger that a) I won’t get the parts back to return the trigger back to its present awesome condition after they “fix” it and b) that Ruger will somehow know that the cylinder is not the same vintage as the revolver and insist on fitting a new one. I have emailed the repair department at Ruger, so we will see what they say.

I might be able to buy this thing from my friend. My plan (if the cylinder fits) is to send it back to Ruger to get refurbished, depending upon how much pitting damage is there. Keep in mind this still belongs to my friend, so I don’t want to do too much to it aside from assessing damage and seeking parts etc. I will see him Tuesday when he gets back from hunting in Montana, and can get a better read on his intentions. What is a fair price to offer? Bearing in mind my future expenditures to get it back shipshape. I’m thinking $50. Too low? Too high? He got it maybe 15 years ago and hadn’t done anything with it until now.

I will get some pics posted as soon as I figure out Imgur again.