OK, we've talked about it and after weighing the pros and cons I'm going to try to produce a full bore ZINC slug load for a 3" rifled 12 guage. I just ordered this mold from Accurate Molds.
http://www.accuratemolds.com/bullet_...=73-860B-D.png
From what I can read the Zamak 3 alloy looks like the best choice, so this will be coming soon.
http://www.rotometals.com/product-p/zamak-3-ingots.htm
If I can cast these it should yield a slug that weighs 1.31 oz. There's a 3 week turnaround on the mold. In the mean time I will aqcuire a new clean pot and ladle to insure no contamination. Until I actually begin casting trials, comments are welcome, especially about load recommendations and wad column composition. My powder choices are Steel, Longshot and 800-X. Wish me luck and let's have at it!