Just a few thoughts in pictures. We'd like to see YOUR setup for boring cannon/mortar barrels, here's part of mine.
First, the boring bar holder. Home made. Holds two sizes of boring bars. Could hold large diameter bit, but there are better ways of doing that. CRS in chuck is 6" long 5.25" diameter. Steady rest just in front of steel is too small - only goes up to about 4" diameter.
http://www.hunt101.com/img/197385.jpg
Selection of boring bars. One by tape measure fits into previous boring bar holder. Other one at left needs holder made for it. Note how cutters are angled and attached in both bars.
http://www.hunt101.com/img/197387.jpg
Boring bar cutter:
The boring bar is a 1" diameter precision rod from a dot-matrix printer. The holder for the cutter is from a 1" diameter bolt. machined a slot and hold for thru-bolt to hold carbide cutter insert. Head attaches to shaft by a section of bolt threaded into each.
http://www.hunt101.com/img/197391.jpg
