A couple years ago I picked up a #2 rolling block in .44 rimfire. After converting to centerfire I needed to make brass. I started with .303 Savage brass that had been converted to .44 Ballard extra long by Buffalo Arms. It was shortened to .965", then put in the lathe and the excessively thick neck turned down. This is a video I made showing my process.
Your Dunlap lathe should be fine for doing the same thing.
https://youtu.be/iVzb4WopeAM