Sarg,

I can probabally provide some insite. Can you provide more information on what you have? Ball & Shot?, Bore rifle, who are the makers? are they hammer, boxlock, or sidelock? etc? What are the twist rates and rifling types? Is there any dram or bullet weight data on the flats, rib or barrel? What do the guns weigh?

The more specific you are, the more I can help if you need it.

In the eight you could probabally get away with a pure lead bullet between .835 and .840 as they will bump up to fill the groves upon firing. But let's hear what you have...