A .405" Winchester case with tubing soldered to it, would be .490". Simple matter to turn that to .487" as that case wall is .015" thick. (that is, if the brass tube fits closely to the .460" base of the .405 Winchester case.
The .405"s rim dia. is .543.
Of course, a .30/40 case head would come out about perfect - maybe, depending on the internal case diameter of the tube.