The .23-40 that Red Cornelison shot so well for so long even competing against and beating the PPC's is a .223 case with the shoulder moved back slightly making a longer neck than the parent .223. The 40 on the designation of the cartridge is for the 40 degree shoulder. When I was selling Red's chambering reamers for Bonnie, I bought his .23-40 reamers. There were 4 or 5 different variations of the reamer with different freebore, body and neck dimensions. Unfortunately, the reamers weren't marked as to which reamer was the one that Red liked to use the best. I chambered a barrel for one once, but have not pursued it any further. I had planned to build a rifle dedicated to the .23-40 to give it a good shot to try to figure out which reamer would work the best, but it's been pretty well buried for awhile. Maybe once we have our house finished, I'll be able to get back on that project. Still have a few customers rifles to get out that come first though before I start on my own projects. By the way, we put the last of the tarpaper on the roof of the house last week and we are more or less in the dry on the house. More or less because a little snow still blew into it last night, but at least its in the dry from rain as long as it's not blowing in sideways.