A friend was asking about this idea. Rossi did these for a short run on the 1892. Wondered if the same result could be achieved taking a Rossi 1892 as a donor and rebarelling and whatever else is needed. I dont know the specific dimensions of the Rossi's nor the 480 ruger. If anyone has any input feel free to chime in

The 480 rim diameter is roughly 1/32" larger than the diameter that the Winchester 92 tube was designed for.
Do not know where you will find a special thin wall tube or a larger diameter tube.

That also brings up the main issue of reducing the thickness between the barrel thread OD and the tube wall OD in the receiver.

Suspect that simply due to the thinner barrel shank wall thickness and the thinner receiver webb thickness is why Rossi stopped making that caliber. Just too much pressure for the thinner walls will create bulged chambers and other nasty things to happen.

J Wisner

The 480 is a reasonably low pressure round if loaded to factory level pressure. I have a Rossi in 480, the mag tube is threaded into the receiver. The mag tube is also larger then the barrel at the muzzle.
I measured the receiver at the barrel shank, before shooting it. With a little over 1800 rounds through it, the measurements have not changed. They claimed a different heat treat for the 480 and 454 casull rifles. Who knows if that is actually true.