Putting on a new tube is the easiest.

I have a #1 in 50 AK and one in 500NE both are fine rounds. If you go to a 50/70 and want to lengthen the chamber at some point you can go to 50/90 Sharps or 50/110 but not to a 50 AK as the base of the 50 AK is smaller than the old buffalo rounds. Starline makes affordable brass for all of brass for all but the 500 NE. All of them in a #1 will give you all the fun you want:-) Good luck on your project.