Hi Peter,
I am going to try IC's first then cylinder bore.As for rifled tubes,
I might try them later, the Brenneke rounds I have are for smooth bores.

With either the 3" or 2 3/4's I am hoping to get both barrels to place
2 rounds each into a 6 in. circle at 50 yards,then sight one barrel for
up to 100 yards if possible.

I know this is a long shot but it will be interesting to try,and if it
works out I may consider adding a set of sights.