Thanks for all the help. I've been busy so I haven't had a chance to do much more on it yet. I think I'll call some barrel makers tomorrow.

Does anyone have any suggestions on barrel length, width across the flats, or anything else for an 8 bore barrel or a 12 bore barrel?

What would be a good weight for an 8 bore single barrel rifle? What about for a 12 bore for very heavy charges (as in over 200 grains)?

Thanks again.