I have just received notice that the 2-1/4" round ball mould I had made is complete and should be shipped next week. I talked Glenn of LEM moulds into making one last mould for us. I asked this one be made a bit more robust than past moulds.
When it arrives I will forward it to RotoMetals and have them cast up some samples for me to evaluate and measure.. I will send at least one sample to Trey to test in his cannon.
I have tried to contact Jack at Hern Iron Works to get a sample of his barrel liner to test a ball in. He hasn't got back to me yet. When the mould gets here I will try to contact him again.
Rotometal is asking $8.99 for as cast, un finished 2.56" popcan round ball, $12.99 sanded and finished.
Using George's round ball weight calculator:
http://gunneyg.info/html/ShotWeight.htm, The popcan ball should weigh 2 1/8 lbs.
These balls at 2-1/4" should be right around 1.44 pounds.
I don't have any idea what they might cost. My guess is some where around $6-$7 each