Bill,
Yes, Michael had posted about shooting the King (thanks Thaine for the link) and I had tried it once. Unfortunately the mold Michael had used which was either made by John Wills or modified by him was sold before I got the rifle. I have not tried the unknown and just got the Griffin at Tulsa. The seller of the Griffin had tried cast bullets and wasn't impressed but when I got home I think I know why. There is a lot of copper fouling in the barrel which I need to clean out before I try it.
It is on my list of things to get done this year, shoot a bunch of my sporters with cast bullets. I plan to use the paper plate targets like Michael did.
Dan