One other thing....check the volume of the reformed 30-30 cases against the 375 cases. you will find more capacity, the 375 cases are thicker, so beware in your loadings.
I have been sucessfully in re-forming by first anealing the case mouths. Stand the cases up in a cookie tray filled with water. Use a propane torch to heat the shoulder neck area cherry, then tap it with the tourch tip to tip it over into the water to quench it. When done, clean, dry and load as normal. I once made up a hundred 256 win cases from 357 mag brass doing this. Now THATS a hard case to make!!!
CW