You don't swage "down". You swage up, and draw down. Each step of creating a bullet via swaging results in a slightly larger diameter "bullet". Getting a press and set of draw dies to do what you want - if it's even practical to do it - will be expensive, and the process will be time consuming, because you will need to be very careful not to crack the dies. WW lead is considered very hard for swaging purposes. As others have said, doing this with pure lead would be difficult. Using WW with a hand press just ain't practical. Even using a hydraulic press wouldn't be easy. And modifying an existing mould is just not practical, either. Plus, the lube grooves will be damaged, too. The only style of bullet I would even consider trying to draw down would be a paper patch bullet, as it has no grooves. If you were trying to do this with something like a .22-cal bullet made of 1:40, maybe 1:30 tops, you could probably get away with it. Ask anyone who produces lead wire how difficult it is to draw pure lead. I have a Corbin CSP-2 press and I wouldn't even try to make my own lead wire. It's much cheaper and easier to buy it from someone who has the right tools to do it. Casting my own cores is cheaper still.
Why don't you just buy a mould that drops what you want? Even if you have to have it custom made, it will be much, much cheaper and much, much easier to get the results you want - a usable bullet that fits your needs. I bet you wouldn't have to look hard to find an existing mould that drops exactly what you want and need.
The amount of money, and time, you'd spend trying to do this as you've described, and get decent results... well... it kinda begs the question - Why?
