>>104367For the collars, some people got the idea to use suitably sized PVC pipe, which uh, sorta worked, though you would have to make sure to shape the things so that they had an angle on their edges, to seat properly on case neck, and they didn't last as long. I speculate that with modern 3D printing technology, it would actually be quite easy to find a polymer which is suitable, and to easily make the shape necessary.
For flame cutting, the simple solution is to simply load 180gr projectiles, just like with .357 Maximum (in spite of this, people didn't want to touch .357 Maximum again, presumably a lot of those were the kind of goofy people who like to load really lightweight projectiles for .357 Magnum to get crazy velocities). This weight of projectiles would even out the pressure curve and basically eliminate flame cutting. All that said, as it would turn out, the flame cutting exhibited by these cartridges wasn't all that big of a deal, kinda unsettling to see that line forming, but it will never get very deep, it won't compromise structural integrity, and it doesn't affect accuracy.
Here's a Ruger Blackhawk with a .357-44 Bobcat Magnum cylinder, it also features some old Pachmayr Presentation grips, and what appears to be an extra wide trigger, I speculate that this revolver would be very comfortable and easy to shoot for how much punch it packs. Slap a red dot sight or a suitable long eye-relief scope on it, and it'd be a great hunting revolver.
To get these cylinders, you'd send in a .357 Magnum cylinder for something like a Blackhawk or a Redhawk, and they'd machine it out for you, then send it back, you could also order the loading kit and rings to go with it when sending it back.