I would use a Lyman top punch meant for any of the Lyman 38 wadcutters--like #358495 or #358063. I had Buckshot make me a set of flat-faced top punches in a variety of calibers about 25 years ago, I use those for #358432.
Johnny, our very own Keith B makes and sells hollow top punches that you can fill with two-part epoxy or hot melt glue and make an impression of any bullet, for an exact fit. Inexpensive and easy.