Having reformed many .45-70 cases into .33 Winchester cases and having used both a RCBS forming die and a .38-56 sizing die, I found the case forming easier using the .38-56 sizing die. The forming die will work but the .38-56 just goes easier. Use Imperial Sizing Lube in a very lite coating to avoid lube wrinkles. You are going to run the case in and out of the sizing die several times. Each insertion into the sizing die the case goes further in until you have a .38-56 formed case,. Each time out wipe the case of lube and then apply another very lite coat of lube. When finally fully inserted in the .38-56 sizing die begin the entire process over again using the .33 Winchester sizing die. This step goes quicker than the first. Remember to remove the decapping pins from the sizing dies except for the last pass through the .33 Winchester sizing die. I have read that some claim they can form the case in one pass. I can’t do it. Probably because I don’t want a case struck in the die and wrinkled like a prune. Remember, you are going from an ID of .458” to an ID of .338”. That is a lot of inside reduction along with shoulder forming. When finally formed you trim to length and you may have to ream the necks. When finished they are a thing of beauty. Well worth the effort.
Last edited by sjc; 04/05/22. Reason: Added information
