The slug mold design isn't the concern, only that even with a good amount of pressure the lead would not truely form into a single mass. The process would be the same as any swaging process, except it would involve raw shot rather than a solid ingot or pellet. I am worried it will be like when play-dough is left out too long to where it will not readily blend when pressed together and instead stays as separate pieces that can easily be pulled apart. Kindof like it has a thin dry "crust" over its surface. Does that make sense?
I did try making a small test mold once, which relied on the pressure of a bolt being tightened down to squish the shot together into a cavity. That worked out to maybe 500-700lbs of force, and while the shot did stick together firmly enough to stay in one piece in my hand, it did still look like a miniature bunch of grapes and would break apart when dropped or even if I pulled on it with my fingers. But, if I'd be working with a 6-ton press I'd be looking at about 20x the amount of pressure, and I'd even be willing to invest in a larger press to make it work, because the savings would pay off extremely quickly compared to store-bought slugs.
It would cost me about $.13 per shell to load those slugs, vs $1 per shell for the cheapest (least effective) factory slug loads (while comparably effect ones are more like $1.4 per shell). Thus, it would only take about 235 shells before I broke even, which is really only a handfull of range trips. I could start with store-bought cast bullets and load for about $.20 per shell, which still wouldn't be that bad, but it would obviously take me longer to break even and wouldn't in any way help me get through these big bags of shot I've got lying around from before I took a break from reloading :P .
I did find some engineering article on cold-sintering (compressing powered metal into solids at room temp), and it did say that pretty much all metals can be cold-sintered at.... 435,000 PSI :P . For a .41-diameter slug, that would require a bit under 60,000lbs of force, or 30 tons. So, if something like, say, steel (an iron alloy) might require 50,000lbs of force to sinter, lead should be workable with much less force, which means a basic shop press should provide enough force to do it with ease. Now to decide how big of a shop press I need a 6-ton, 12-ton, or 20-ton press.
So, at least know I have good reason to believe it is possible. The biggest problem I've read that I might face is that the presence of Lead Oxide on the surfaces of each pellet might prevent them from adhering together.
Last edited by Lindenwood; 01-10-2011 at 03:05 AM.