I'm sure most of you are familiar with the Lee Universal Expander Die. Its really a flaring die with a two different flaring plugs. Its a handy tool, but I don't always want a flare. I'm working on my #2 rolling block's  44 cartridge, and do not have an expander of the proper size. I was looking at NOE's web site and saw they have expander plugs for the Lee universal expander die. These are true expanders, not flaring plugs. We I thought I'd try making one myself. So I turned some mild steel to the appropriate shape and made a two-step expander plug. The first step is .407", the second step is .413". The second step will allow the bullet's heel to just enter the case, then as it goes in, it will have a snug fit in the tighter section. After turning and polishing, it was hardened slightly with a torch and oil. It seems to work just fine. I may still order some from NOE. They are very nice and reasonably priced. But I'm glad to know I can make one in a pinch. 

Track of the Wolf sells the Lee expanders and compression die/plugs. Great price, easy to turn down for your needs. I have quit afew of them....

Very nice work, useful die. Use something similar to expand .30-40 to .38-50, .32-40 to .33-47, etc.
Chuck

I also bumped up my Lee expander dies to a good few. I've slowly worked up to quite a few of the NOE plugs and a few of the the TOTW plugs and modified plugs. I think someone out there would do a decent side business making neck sizing bushings that fit in that expander body.