Has anybody tried Hawk Bullets, especially the 200 grain RN with the thin .025 jacket.
http://www.hawkbullets.com/Pricelist.htm Supposedly they use very soft pure copper jackets. These bullets don't have a good reputation among hunters because they tend to shed their jackets but I doubt that that would be a problem at these low velocities. If they need even more expansion maybe get one of those hollowpoint cutters and try cutting a HP into them.